Journal articles on the topic 'Aerial photography in ice surveys'

Aerial photography has been used as a mapping tool in the Antarctic Peninsula region sinre the late 1920s. Following pioneering work by Wilkins in 1928, Ellsworth in 1934 and the British Graham Land Expedition in 1934-37, the Falkland Islands and Dependencies Aerial Survey Expedition carried out extensive aerial photography during the period 1955-57. Since then, many other aerial surveys have been carried out, and the result is an archive of aerial photography that, for some localities, spans 40 years. The production of maps both from different generations of photographs and satellite images has revealed many changes in the extent of ice cover with time. For example, changes in ice shelves such as the Wordie Ice Shelf, Larsen Ice Shelf and Müller Ice Shelf, are well recorded, and the termini of some glaciers have retreated. However, the most pervasive change is the consistent decline in the extent of small bodies of snow and ice. This paper shows how perennial snow or ice cover has decreased in the northern Marguerite Bay area, at 68°S. The correlation of the change with elevation and with climate records from Adelaide and Rothera research stations in the Antarctic Peninsula region is examined.

<p><strong>Abstract.</strong> Today when online satellite images are just a click away, access to geographic information showing the latest images of the globe has dramatically expanded, and historico-geographic research based on such information is flourishing. However, in the study of Chinese history, historical research employing GIS or similar technologies is still in its infancy, since “historical” geographic information with a high degree of precision are lacking. From within the ambit of Chinese geographic information, this report specifically highlights aerial surveys effected during the Republic of China era. To start, we review the history of domestic aerial surveys during R. O. C. period. Then, focusing on Nanjing as an example, we proceed to introduce maps that were actually created based on aerial surveys.</p><p>Chinese aerial surveys date back to around 1930. At the Nationalist Party’s General Assembly in 1929, partisans proposed for the need for aerial surveys. In 1930, the “Aerial Photography and Survey Research Team” was formed within the General Land Survey Department at General Staff Headquarters (National Army of the Republic of China). Consequently, foreign technicians were invited to provide relevant education/training. In June 1931, China’s pioneer initiative in aerial photography took place in Zhejiang province. The aim of aerial surveys in those early days was to create maps for military purposes. Between 1932 and 1939, topographic maps of fortifications located in areas such as the Jiangnan district were prepared. Further, starting from around the same period until the Sino-Japanese War, land registry maps based on aerial surveys were also produced. After the Sino-Japanese War ended, the above-mentioned directorate handed over responsibility for aerial surveys to the Naval General Staff. However, in 1949 the Chinese Communist Party confiscated the maps theretofore produced.</p><p>Although the aerial photographs and the geographic information produced therefrom during the R. O. C. era were seized by the People’s Republic of China, in actuality, some had previously been transferred to Taiwan. The topographic maps of the Nanjing metropolitan area (一萬分一南京城廂附近圖), based on aerial surveys and drawn in 1932, are currently archived at Academia Historica in Taipei. Comprising a total of 16 sheets, these maps were drawn on a scale of 1:10,000 by the General Land Survey Department.</p><p>Similarly, other maps (各省分幅地形圖) produced by the General Land Survey Department, comprising a total of 56 sheets and partly detailing Nanjing, are now in the possession of Academia Sinica in Taipei. There was no information about photographing or making in these maps. But almost the same maps were archived at Library of Congress in Washington D. C. According to those maps at LC, based on aerial photographs taken and surveys conducted in 1933, these topographic maps (1:10,000 scale) were completed in 1936.</p><p>The examples introduced above are topographic maps based on aerial photography. However, starting in 1937, land registry maps were also created. Detailing the outskirts of Nanjing (1:1,000 scale) and comprising a total of 121 sheets, they are now archived at Academia Historica. While the land registry maps were produced in 1937, supplementary surveys were effected following the Sino-Japanese War in 1947.</p><p>Since the geographic information based on aerial surveys during the R. O. C. era in China were precise, they can serve as a source of manifold information. This report only delved into information developed by the Government of the R. O. C., but it is becoming evident that U. S. Armed Forces and Japan also produced geographic information of their own based on aerial surveys. If the comprehensive panorama captured by all three protagonists can be illuminated, further advances in Chinese historico-geographic studies employing geographic information will be forthcoming.</p>

The threatened malleefowl (Leipoa ocellata) constructs a large (often >3 m) incubator mound (nest) that is considered a useful proxy for surveying its presence and abundance in the context of an environmental impact assessment. Here we report on the effectiveness and relative cost of using high-definition aerial photography to search in 3D for malleefowl mounds by comparing results to those of earlier ground-based searches. High-definition colour aerial photography was taken of an area of ~7014 ha and searched in 3D for malleefowl mounds. All 24 active (i.e. in use) malleefowl mounds known before the examination of aerial photography were detected using the new assessment technique. Of the 108 total mounds (active and inactive) known from earlier on-ground surveys, 94 (87%) were recorded using the new technique. Mounds not detected were all old and weathered, many barely above ground level and some with vegetation growing in the crater. Approximately 6.3% of the identifications considered ‘confident’ and ~35.0% considered ‘potential’ based on the aerial photography proved to be false positives. The cost of detecting malleefowl mounds using the interpretation of high-definition 3D colour aerial photography and then subsequently examining these areas on the ground is appreciably cheaper than on-ground grid searches.

Logistically demanding and expensive wildlife surveys should ideally yield defensible estimates. Here, we show how simulation can be used to evaluate alternative survey designs for estimating wildlife abundance. Specifically, we evaluate the potential of instrument-based aerial surveys (combining infrared imagery with high-resolution digital photography to detect and identify species) for estimating abundance of polar bears and seals in the Chukchi Sea. We investigate the consequences of different levels of survey effort, flight track allocation and model configuration on bias and precision of abundance estimators. For bearded seals (0.07 animals km −2 ) and ringed seals (1.29 animals km −2 ), we find that eight flights traversing ≈7840 km are sufficient to achieve target precision levels (coefficient of variation (CV)<20%) for a 2.94×10 5 km 2 study area. For polar bears (provisionally, 0.003 animals km −2 ), 12 flights traversing ≈11 760 km resulted in CVs ranging from 28 to 35%. Estimators were relatively unbiased with similar precision over different flight track allocation strategies and estimation models, although some combinations had superior performance. These findings suggest that instrument-based aerial surveys may provide a viable means for monitoring seal and polar bear populations on the surface of the sea ice over large Arctic regions. More broadly, our simulation-based approach to evaluating survey designs can serve as a template for biologists designing their own surveys.

Abstract Since the 1960s pup production of harp seals Pagophilus groenlandicus in the White Sea was estimated from aerial photographic surveys of visible adult females on the ice. Adult abundance estimations were underestimated because an unknown number of females were in the water during the survey. The absence of a reliable estimation of pup production constrained management initiatives. Aerial photographic surveys of whelping harp seals were conducted in the White Sea 10–12 March 2000. Using a systematic strip transect survey design approach, the number of pups present was estimated as 294 914 with a standard error (s.e.) of 36 168. When pups caught by Russian sealers in the White Sea before the aerial surveys (30 729 pups) were included the total estimated number of pups was 325 643 (s.e. 36 168), whereas the number of adult harp seals was 215 943 (s.e. 22 630). The pup estimate was not corrected for pups born after the survey, but this was not considered to be significant. The new estimation of pup production is higher than thought earlier.

Linear engineering facilities, such as gas transportation systems, extend from 30 to 500 metres in width and several hundred kilometres in length. Such routes pass through areas characterized by sufficiently diverse engineering, geological, geocryological and seismotectonic conditions. The safe and reliable functioning of gas transportation systems is ensured by their regular monitoring to prevent the development of hazardous exogenous geological processes. In particular, when monitoring ice formation, the greatest efficiency can be achieved by using unmanned aerial vehicles for low-altitude aerial surveys. In this research, remote sensing methods based on unmanned technologies were applied to assess the aufeis hazard in a section of the Power of Siberia gas pipeline in South Yakutia. The authors’ successful experience of using unmanned systems during an aeromagnetic exploration of iron ore deposits in South Yakutia was also considered. A series of studies, including georadar and electrical exploration profiling, as well as thermal imaging and high-resolution aerial photography by an aerial complex, was conducted to assess the dynamics of ice development over time in the area under study and to establish the signs of a developing hazardous process.

Polar bears are of international conservation concern due to climate change but are difficult to study because of low densities and an expansive, circumpolar distribution. In a collaborative U.S.-Russian effort in spring of 2016, we used aerial surveys to detect and estimate the abundance of polar bears on sea ice in the Chukchi Sea. Our surveys used a combination of thermal imagery, digital photography, and human observations. Using spatio-temporal statistical models that related bear and track densities to physiographic and biological covariates (e.g., sea ice extent, resource selection functions derived from satellite tags), we predicted abundance and spatial distribution throughout our study area. Estimates of 2016 abundance (N ^ *) ranged from 3,435 (95% CI: 2,300-5,131) to 5,444 (95% CI: 3,636-8,152) depending on the proportion of bears assumed to be missed on the transect line during Russian surveys (g(0)). Our point estimates are larger than, but of similar magnitude to, a recent estimate for the period 2008-2016 (N ^ * = 2 , 937; 95% CI 1,522-5,944) derived from an integrated population model applied to a slightly smaller area. Although a number of factors (e.g., equipment issues, differing platforms, low sample sizes, size of the study area relative to sampling effort) required us to make a number of assumptions to generate estimates, it establishes a useful lower bound for abundance, and suggests high spring polar bear densities on sea ice in Russian waters south of Wrangell Island. With future improvements, we suggest that springtime aerial surveys may represent a plausible avenue for studying abundance and distribution of polar bears and their prey over large, remote areas.

The results of engineering surveys in the area of the Mirny and Progress stations and fi eld base Molodyozhnaya are discussed in the paper. During the austral summer fi eld season of the 62nd RAE (2016/17) wide complex of the scientifi c and applied research has been carried out. It included the engineering, aerial photography, glaciological, drilling, geodetic and GPR investigations to ensure the safety of transport operations in the area of Russian stations Mirny and Progress (East Antarctica). The scientifi c tests to study sea ice have been carried out on the frozen water area of Nella Fjord, near Progress Station.

<p><strong>Abstract.</strong> Rock glaciers are creep phenomena of mountain permafrost. Typically, these landforms look like lava flows from a bird’s eye view. Active rock glaciers move downslope with flow velocities in the range of few centimeters to several meters per year. Thus, large masses of rock and ice can be gradually transported down-valley. In this paper we present a comparative study analyzing surface change for Tschadinhorn rock glacier, a relatively fast moving rock glacier located in the Hohe Tauern Range of the Austrian Alps. Aerial photographs (1954&amp;ndash;2017) of both metric (conventional) and non-metric (UAV-based) aerial surveys were compared to derive multi-annual to annual flow vector fields and surface height change. For each time interval given we computed a single representative value for flow velocity and, if applicable, also for area-wide surface height change, i.e. volume change. The velocity graph obtained represents the temporal evolution of the kinematics of the rock glacier with good discrimination. Volume change was difficult to quantify since temporal changes were rather small and close to insignificance. The precision and accuracy of the results obtained were numerically quantified. Our study showed that for the Tschadinhorn rock glacier UAV-based aerial surveys can substitute conventional aerial surveys as carried out by national mapping agencies, such as the Austrian Federal Office of Metrology and Surveying (BEV). Thus, UAV-based aerial surveys can help to bridge the data gap between regular aerial surveys. The high accuracy of the UAV-derived results would even allow intra-annual change detection of flow velocity.</p>

We conducted surveys in 1983 and 1984 of submersed macrophyte communities off six islands in the St. Clair and Detroit rivers using low altitude aerial photography and ground-truth collections. Sample collections in 1984 followed one of the coldest winters on record, during which ice up to 4 m thick developed in areas that were normally ice-free. Growth of many of the 20 taxa collected was delayed in the spring of 1984, as compared with the spring of 1983. By September 1984, however, total abundance of all taxa was equal to or greater than that in 1983. The location, size, and shape of plant beds in September 1984 were similar to those in 1983. We concluded that the unusual ice jam in early spring of 1984 had little, if any, permanent effect on submersed macrophytes in the St. Clair and Detroit rivers.

Northwest Atlantic harp seal, Phoca groenlandica, pup production was estimated from aerial surveys flown off eastern Newfoundland ("Front") and in the Gulf of St. Lawrence ("Gulf") during March 1990. One visual and two independent photographic estimates were obtained at the Front; a single photographic estimate was obtained in the Gulf. Photographic estimates were corrected for misidentified pups by comparing black-and-white photographs with ultraviolet imagery. Estimates were also corrected for pups absent from the ice at the time of the survey using distinct age-related developmental stages. Stage durations in the Gulf appeared consistent with previous studies but were increased by 30% to improve the fit to staging data collected at the Front. The best estimate of pup production at the Front was obtained from the visual surveys. A total of 467 000 (SE = 31 000) pups were born in three whelping concentrations. The photographic estimates were comparable. Pup production estimates for the southern (Magdalen Island) and northern (Mecatina) Gulf whelping patches were 106 000 (SE = 23 000) and 4 400 (SE = 1300), respectively. Thus, total pup production was estimated to be 578 000 (SE = 39 000).

AbstractGeomorphological and glaciological features are represented on a georeferenced satellite image mosaic of the Mount Murchison quadrangle, northern Victoria Land, Antarctica (73–74˚ S, 162–166˚30' E), at a scale of 1 : 250 000. Landforms and deposits of glacial and periglacial environments, forms related to mass wasting, wind action, weathering and geological structures are identified and mapped. The chronological sequence of landforms and deposits, morphography and lithology is also indicated. Glacier velocities (up to 180 ma–1) and ice-front fluctuations (1964–99) were determined by analysis of aerial photography and satellite imagery. Airborne radar surveys reveal that the greatest ice thickness (about 1500 m) is located in the grounding zone of Aviator Glacier. Up to 1000 mof ice bury the subglacial relief of Deception Plateau, Hercules Névé and the Deep Freeze Range. Snow accumulation rates (average = 170 kg m–2 a–1) exhibit an overall negative correlation with altitude and distance from the coast. The relationships among relict erosional landforms and volcanic activity provide chronological constraints for the palaeogeographic evolution of this sector of the Transantarctic Mountains.

AbstractThe emperor penguin colony at Coulman Island is reputedly the largest known. This reputation is based on intermittent ground and aerial surveys performed since 1958. From an aerial survey obtained on 28 October 2010 we discovered that the total number of chicks was 56% of the lowest previous estimate of 2006 and only 41% of the most recent estimate in 2008. All of the counts tallied since 1983 were determined either by ground counts or from aerial film or digital photographs, or estimates from adult counts. We also determined the sea ice conditions in autumn, which is close to the time the adults arrive to breed. We present three hypotheses of what might have happened from 2008–10 to cause the step change in chick production, the small recovery of chick numbers in 2011, and the complete recovery of number of adults from 2010–11. We conclude that local circumstances may have strongly influenced the breeding behaviour of the emperor penguins in 2010 and to a lesser degree in 2011 when many adults elected not to breed.

The use of unmanned aerial systems (UAS) in glaciology and cryology, as well as studying and monitoring of polar regions is one of the most rapidly developing areas of the unmanned aerial industry. An aerial photogeodetic team of the 67th Russian Antarctic Expedition (RAE) solved two main interrelated tasks: 1) field tests of the newest Russian UAS Geoscan 701 in Antarctic conditions and 2) carrying out unmanned aerial surveys of two Antarctic territories, characterized by fundamentally different natural conditions, in order to obtain their high-precision orthomosaics and digital elevation models (DEMs) of an ultra-high resolution. On 15 January 2022, we carried out an unmanned aerial survey of two adjacent Antarctic maritime oases Molodezhny and Vecherny and surrounding areas of the glacier (Enderby Land, East Antarctica). From 26 January to 16 February 2022, we performed an unmanned aerial survey of the Fildes Peninsula (the southwestern, free of ice cover portion of the King George Island, South Shetland Islands, West Antarctica). The survey was complicated by severe meteorological conditions (low clouds, fog, strong winds, and precipitation). Field tests of UAS Geoscan 701 have shown that the system can be successfully used for unmanned aerial survey in polar regions. After in-office photogrammetric processing of the obtained materials, orthomosaics and DEMs of the indicated territories will be obtained with a resolution of 10 and 25 cm, respectively. These will be used for creation of modern large-scale topographic maps, photographic maps, three-dimensional and geomorphometric modeling of these territories, as well as operational and scientific activities of the RAE.

Pup production of hooded seals (Cystophora cristata) in the Northwest Atlantic was estimated by aerial survey. Simultaneous surveys and the collection of ground-truth data were conducted in March 1984 in both major whelping areas, namely the floe ice in the Davis Strait and off northeastern Newfoundland (the Front). Abundance estimates were obtained from both fixed-wing photographic and helicopter sighting surveys using a strip survey method for unequal-sized sampling units. These abundance estimates were corrected to account for pups which had left the ice and those pups which had yet to be born in each area. A maximum likelihood method was used to combine estimates of abundance from several surveys with estimates of the number of pups in each developmental stage to obtain an estimate of total production. This method weighted each survey point estimate of abundance by the estimated sampling variance and each estimate of the proportion of pups on the ice in each stage by the sample size corrected for loss of degrees of freedom associated with the sampling design. Total production at the Front was estimated to be 62 400 with 95% confidence limits of 43 700 to 89 400 and in the Davis Strait was 19 000 with a 95% confidence interval of 14 000 to 23 000. Total pup production estimates for the Front and Davis Strait are likely underestimates for several reasons, but are substantially higher than those previously assumed for the Northwest Atlantic.

Abstract From 14 March to 6 April 2002 aerial surveys were carried out in the Greenland Sea pack ice (referred to as the “West Ice”), to assess the pup production of the Greenland Sea population of harp seals, Pagophilus groenlandicus. One fixed-wing twin-engined aircraft was used for reconnaissance flights and photographic strip transect surveys of the whelping patches once they had been located and identified. A helicopter assisted in the reconnaissance flights, and was used subsequently to fly visual strip transect surveys over the whelping patches. The helicopter was also used to collect data for estimating the distribution of births over time. Three harp seal breeding patches (A, B, and C) were located and surveyed either visually or photographically. Results from the staging flights suggest that the majority of harp seal females in the Greenland Sea whelped between 16 and 21 March. The calculated temporal distribution of births were used to correct the estimates obtained for Patch B. No correction was considered necessary for Patch A. No staging was performed in Patch C; the estimate obtained for this patch may, therefore, be slightly negatively biased. The total estimate of pup production, including the visual survey of Patch A, both visual and photographic surveys of Patch B, and photographic survey of Patch C, was 98 500 (s.e. = 16 800), giving a coefficient of variation of 17.9% for the survey. Adding the obtained Greenland Sea pup production estimate to recent estimates obtained using similar methods in the Northwest Atlantic (in 1999) and in the Barents Sea/White Sea (in 2002), it appears that the entire North Atlantic harp seal pup production, as determined at the turn of the century, is at least 1.4 million animals per year.

In this paper, we estimate the pup production of harp seals ( Pagophilus groenlandicus ) using generalized additive models (GAMs) based on thin-plate regression splines. The spatial distribution of seal pups in a patch is modelled using GAMs, and the pup production is estimated by numerically integrating the model over a fine grid area of the patch. Closed form expression for estimation of the the standard error of the pup production estimate is derived. The estimators are applied to simulated seal populations to investigate their properties. The results show that the proposed pup production estimator is comparable with the conventional pup production estimator. However, the bias of the standard error estimator of the proposed method is much lower than the bias of the conventional standard error estimator. The decrease of standard error bias results in a considerable reduction of the coefficient of variation estimate using the proposed GAM-based method. The proposed method is also applied to real survey data of harp seals obtained from aerial surveys in the Greenland Sea pack ice in 2002. We show that the number of pups counted from aerial photographs possess a good fit to the negative binomial distribution when a logarithmic link function is applied. The approach described here is applicable to many situations where georeferenced counts or measurements are available.

AbstractGlaciers depicted on old maps reveal their historical extents, before the advent of aerial and satellite remote sensing. Digital glacier inventories produced from these maps can be employed in assessments of centennial-scale glacier change. This study reconstructs the ~1899 (covering the period 1882–1916) glacier extent in Nordland, northern Norway, from historical gradteigskart maps, with an emphasis on examining the accuracy of the mapped glaciers. Glacier outlines were digitised from georectified scans of the analogue maps in a raster graphics editor and were subsequently inventoried in a GIS. The accuracy of the historical glacier extent was established from written descriptions and landscape photographs created during the original field surveys, and further validated against independent glacier outlines of (1) the maximum Little Ice Age extent derived from geomorphological evidence, and (2) the 1945 extent derived from vertical aerial photographs. An overall uncertainty of ±17% is associated with our inventory. Nordland's glaciers covered an area of 1712 ± 291 km2 in 1899. By 2000, total ice cover had decreased by 47% (807 ± 137 km2) at a rate of 6% 10 a−1 (80 ± 14 km2 10 a−1). The approach presented here may serve as a blueprint for future studies intending to derive glacier inventories from historical maps.

Resource development in Arctic waters is proceeding rapidly leading to increased interactions with Arctic wildlife. As sea ice extent decreases, the demand for shipping and ice-breaking operations will expand into winter and spring with greater impact on ice-dependent pinnipeds. However, knowledge of the distribution of these species, such as ringed seals (Pusa hispida (Schreber, 1775)), during spring within areas of resource development is lacking. Baffinland Iron Mines Corporation’s Mary River iron ore port in southern Milne Inlet, Nunavut opened in 2015 with proposed ice-breaking activities in spring — an important period in ringed seal seasonal life-history. We conducted infrared and photographic aerial surveys in June 2016 and 2017 to overlay the proposed ice-breaking route with ringed seal hotspots (i.e., areas of higher density). We identified four areas of overlap where proposed ice-breaking would traverse through ringed seal hotspots: eastern and western Eclipse Sound (a ringed seal pupping ground identified by local knowledge), the middle of Milne Inlet, and southern Milne Inlet. We identified potential negative implications of spring ice-breaking operations on ringed seals such as displacement, separation of mothers and pups, destruction of resting and birth lairs, and vessel–seal collisions. Results are relevant to policy decision-makers who can develop mitigation strategies in the rapidly melting and developing Arctic.

Between 1925 and 1980, landscape ecology underwent important changes through the gradual imposition of the view from above, through the uses of aerial photography. A new concept emerged, “the smallest unit of landscape,” also called ecotope and land unit, expressing a direct visual grasp of the landscape. This article compares the view from above as introduced and promoted by geographers Carl Troll and Isaak Zonneveld, with its (problematic) history vis-à-vis a school of ecology, i.e., plant sociology, led by Josias Braun-Blanquet and Reinhold Tüxen. This school’s internal struggles with balancing the physiognomic gaze (at the ground) and numerical methods are discussed. In comparison, the geographers based themselves on the mechanical objectivity of standardized aerial surveys, whereas the plant sociologists relied on their subjective expert judgment of plant recognition together with the structural objectivity of their numerical methods. An important communality of both schools was their inductive building of a landscape from its constituent landscape fragments. Landscape fragments were identified through abstraction and categorization, emanating from a taxonomical style of science.

AbstractRapid thinning and velocity increase on major Greenland outlet glaciers during the last two decades may indicate that these glaciers became unstable as a consequence of the Jakobshavn effect (Hughes, 1986), with terminus retreat leading to increased discharge from the interior and consequent further thinning and retreat. To assess whether recent trends deviate from longer-term behavior, we measured glacier surface elevations and terminus positions for Jakobshavn Isbræ, West Greenland, using historical photographs acquired in 1944, 1953, 1959, 1964 and 1985. These results were combined with data from historical records, aerial photographs, ground surveys, airborne laser altimetry and field mapping of lateral moraines and trimlines, to reconstruct the history of changes since the Little Ice Age (LIA). We identified three periods of rapid thinning since the LIA: 1902–13, 1930–59 and 1999–present. During the first half of the 20th century, the calving front appears to have been grounded and it started to float during the late 1940s. The south and north tributaries exhibit different behavior. For example, the north tributary was thinning between 1959 and 1985 during a period when the calving front was stationary and the south tributary was in balance. The record of intermittent thinning, combined with changes in ice-marginal extent and position of the calving front, together with changes in velocity, imply that the behavior of the lower parts of this glacier represents a complex ice-dynamical response to local climate forcings and interactions with drainage from the interior.

AbstractNinety-six mummified crabeater seals discovered at Seymour Island (Isla Marambio) are reported. Each specimen was georeferenced, photographed and assigned to five different taphonomic states. Previous work stated that seals at Seymour Island get stranded inland around the breeding season. However, it is not clear if the species breeds in this area. The abundance of crabeater seals and the ice condition along Admiralty Sound (Estrecho Bouchard) were obtained by aerial surveys during spring (2015–17). It appears that the species uses the strait as a passage to breeding grounds. Under heavy ice conditions, the seals become stranded in the middle section of this strait and wander inland through a valley that represents the mouth of an ephemeral stream that ends at the pack ice level. This situation was observed in 2014 and 2015 when recently dead seals were found, evidencing that this natural trap is still active. Nonetheless, in 2016 and 2017, during an early breakup of Admiralty Sound, the seals that remained in the area were more numerous than in 2015 but they did not get stranded inland. This early breakup may encourage the seals to breed there in the presence of open water areas with ice floes.

Abstract. Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next 5 years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2 and the smaller one 2.93 km2; the Murray and Simmons ice caps covered 4.37 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 and 25 %, likely reflecting their higher elevation. Consistent with findings from other glaciological studies in the Queen Elizabeth Islands, ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

Abstract. The measured rise in eustatic sea level over the 20th century was dominated by mass loss from the world's mountain glaciers and ice caps, and predictions suggest that these fresh water reservoirs will remain significant into the 21st century. However, estimates of this mass transfer to the ocean are based on a limited number of observations extrapolated to represent not only regional changes but often changes across individual glaciers. Combining high resolution elevation data from contemporary laser-altimetry surveys and archived aerial photography makes it possible to measure historical changes across a glacier's entire surface. Here we present a high spatial resolution time-series for six Arctic glaciers in the Svalbard Archipelago spanning 1961 to 2005. We find increasing thinning rates before and after 1990 with elevation losses occurring most notably in the glaciers' upper reaches. In the absence of a clear meteorological driver, we recommend further investigation into a possible albedo amplification of prevailing meteorological trends to explain these higher elevation changes, which could have important consequences on the region's mass balance due to the sensitivity of its hypsometric distribution. However, the strong influence of decadal-scale variability, while explaining lower rates of mass loss reported in earlier studies, highlights that caution must be exercised when interpreting thinning rates when averaged over long periods.

Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2&ndash;3°C since the 1950’s, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. <br><br> Environmental monitoring in Canada’s North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. <br><br> Unmanned aerial vehicle (UAV) technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1&ndash;5 cm) and coverage that can be directly related to satellite imagery (1&ndash;10 km²). Unlike satellite measurements, UAVs permit frequent surveys (e.g. for monitoring vegetation phenology, fires, and hydrology), are not constrained by repeat cycle or cloud cover, can be rapidly deployed following a significant event, and are better suited than manned aircraft for mapping small areas. UAVs are becoming more common for agriculture, law enforcement, and marketing, but their use in the Arctic is still rare and represents untapped technology for northern mapping, monitoring, and environmental research. <br><br> We are conducting surveys over a range of sensitive or changing northern landscapes using a variety of UAV multicopter platforms and small sensors. Survey targets include retrogressive thaw slumps, tundra shrub vegetation, recently burned vegetation, road infrastructure, and snow. Working with scientific partners involved in northern monitoring programs (NWT CIMP, CHARS, NASA ABOVE, NRCan-GSC) we are investigating the advantages, challenges, and best practices for acquiring high resolution imagery from multicopters to create detailed orthomosaics and co-registered 3D terrain models. Colour and multispectral orthomosaics are being integrated with field measurements and satellite imagery to conduct spatial scaling of environmental parameters. Highly detailed digital terrain models derived using structure from motion (SfM) photogrammetry are being applied to measure thaw slump morphology and change, snow depth, tundra vegetation structure, and surface condition of road infrastructure. <br><br> These surveys and monitoring applications demonstrate that UAV-based photogrammetry is poised to make a rapid contribution to a wide range of northern monitoring and research applications.

Abstract. Changes in the volume and extent of land ice of the Svalbard archipelago have been the subject of considerable research since their sensitivity to changes in climate was first noted. However, the measurement of these changes is often necessarily based on point or profile measurements which may not be representative if extrapolated to a whole catchment or region. Combining high-resolution elevation data from contemporary laser-altimetry surveys and archived aerial photography makes it possible to measure historical changes across a glacier's surface without the need for extrapolation. Here we present a high spatial resolution time-series for six Arctic glaciers in the Svalbard archipelago spanning 1961 to 2005. We find high variability in thinning rates between sites with prevalent elevation changes at all sites averaging −0.59 ± 0.04 m a−1 between 1961–2005. Prior to 1990, ice surface elevation was changing at an average rate of −0.52 ± 0.09 m a−1 which decreased to −0.76 ± 0.10 m a−1 after 1990. Setting the elevation changes against the glaciers' altitude distribution reveals that significant increases in thinning rates are occurring most notably in the glaciers' upper reaches. We find that these changes are coincident with a decrease in winter precipitation at the Longyearbyen meteorological station and could reflect a decrease in albedo or dynamic response to lower accumulation. Further work is required to understand fully the causes of this increase in thinning rates in the glaciers' upper reaches. If on-going and occurring elsewhere in the archipelago, these changes will have a significant effect on the region's future mass balance. Our results highlight the importance of understanding the climatological context of geodetic mass balance measurements and demonstrate the difficulty of using index glaciers to represent regional changes in areas of strong climatological gradients.

Remote-sensing methods in monitoring the glacierization of Mount EI‛ brus are used to produce base and dynamic maps, and to obtain quantitative information (dynamic indices) about the rate, intensity, and variations of the process. The monitoring system is divided, according to scope and territory covered, into small-scale for total glacierization and the periglacial zone, medium-scale for separate glaciers, and large-scale (detailed) for part of the glaciers or sectors of the adjoining slopes. The approximate relationship of even scales is 1 : 4.Small-scale monitoring remote-sensing systems are important for making maps showing the complex characteristics of the glaciological system. A series of maps was produced including geographical, those of high-altitude zones, slope and exposure angles, geological, glaciomorphological, climatic (temperature, precipitation, and winds), distribution of direct solar radiation, hydrological (source of streams), seats of avalanches, and landslides. All these data serve as a cartographical basis in monitoring the glacierization of Mount EI‛ brus. They are compiled from remotely sensed and Earth-based data.Current monitoring on a small scale includes observations of the conditions which determine the existence of the glacial system - this includes data on winter snowfall and the period of snow cover. These observations were obtained from meteorological and resource satellites, and from scanner data of medium and high resolution. Also important are observations of changes in the outline of glaciers, times of snowfall and character of the distribution of snow, and its redistribution due to avalanches and snowstorms. High-resolution space photographs, small-scale aerial photographs, and aerovisual observations provide the data for these observations. It has been determined that the area of the glaciers of Mount El‛ brus has been reduced by 1 % in the last 25 years, i.e. the rate of its deglacierization dropped sharply as compared to preceding decades.The role of quantitative information gains importance in the medium-scale level of monitoring. Topographical maps of separate glaciers compiled from aerial photographs or data from ground stereo-photogrammetric surveys constitute the base maps at this level. The main method used in monitoring were large-scale surveys from aircraft, perspective surveys from helicopters, and phototheodolite surveys. Multi-date surveys of the glaciers provide data about the changes in their outlines and height, the character of their relief, their moraines, the amount of snow accumulation and ablation in separate years, the surface rates of ice flow and their fluctuations. The techniques by which quantitative information is obtained about changes in the glaciers are derived from processing the data of multi-date surveys. The organization and techniques of phototheodolite surveys have been improved. A theory evolved for determining the surface-ice movement by stereo-photogrammetric means and the technique for it has also improved; algorithms and programs for machine processing of the data of multi-date surveys (ground and from aircraft) have been producedAt this level of monitoring, it has been found that the retreat rate of most glaciers has slowed down and several glaciers are now in equilibrium. Several glaciers became active at the beginning of the 1970s and 1980s; this was accompanied by an increase in their height and forward movement. For example, activation of Kyukyurtlyu Glacier has been recorded (higher surface and increasing flow rate) which has caused the glacier to move forward 100 m. Surveys at an interval of 2 years recorded the beginning of the process of retreat of this glacier.Detailed monitoring is used to detect the mechanism of the dynamic processes and to study it on local representative sectors. On a glacier it may take the form of annual surveys of its tongue, which makes it possible to observe the processes of formation of moraines and glacio-fluvial relief. Studies may also be made of the mechanism of the movement of avalanches and landslides, deducing their quantitative characteristics and appraising the results of avalanches and landslides. Multi-date surveys of sectors of the slopes provide information about processes in the periglacial zone. At this level, regularly repeated ground stereo-photogrammetric surveys are the main means of observation.Glaciological remote-sensing monitoring provides a wealth of data for theoretical development in the field of glaciology. It makes it possible to forecast and produce warnings about hazardous processes and phenomena.

Remote-sensing methods in monitoring the glacierization of Mount EI‛ brus are used to produce base and dynamic maps, and to obtain quantitative information (dynamic indices) about the rate, intensity, and variations of the process. The monitoring system is divided, according to scope and territory covered, into small-scale for total glacierization and the periglacial zone, medium-scale for separate glaciers, and large-scale (detailed) for part of the glaciers or sectors of the adjoining slopes. The approximate relationship of even scales is 1 : 4. Small-scale monitoring remote-sensing systems are important for making maps showing the complex characteristics of the glaciological system. A series of maps was produced including geographical, those of high-altitude zones, slope and exposure angles, geological, glaciomorphological, climatic (temperature, precipitation, and winds), distribution of direct solar radiation, hydrological (source of streams), seats of avalanches, and landslides. All these data serve as a cartographical basis in monitoring the glacierization of Mount EI‛ brus. They are compiled from remotely sensed and Earth-based data. Current monitoring on a small scale includes observations of the conditions which determine the existence of the glacial system - this includes data on winter snowfall and the period of snow cover. These observations were obtained from meteorological and resource satellites, and from scanner data of medium and high resolution. Also important are observations of changes in the outline of glaciers, times of snowfall and character of the distribution of snow, and its redistribution due to avalanches and snowstorms. High-resolution space photographs, small-scale aerial photographs, and aerovisual observations provide the data for these observations. It has been determined that the area of the glaciers of Mount El‛ brus has been reduced by 1 % in the last 25 years, i.e. the rate of its deglacierization dropped sharply as compared to preceding decades. The role of quantitative information gains importance in the medium-scale level of monitoring. Topographical maps of separate glaciers compiled from aerial photographs or data from ground stereo-photogrammetric surveys constitute the base maps at this level. The main method used in monitoring were large-scale surveys from aircraft, perspective surveys from helicopters, and phototheodolite surveys. Multi-date surveys of the glaciers provide data about the changes in their outlines and height, the character of their relief, their moraines, the amount of snow accumulation and ablation in separate years, the surface rates of ice flow and their fluctuations. The techniques by which quantitative information is obtained about changes in the glaciers are derived from processing the data of multi-date surveys. The organization and techniques of phototheodolite surveys have been improved. A theory evolved for determining the surface-ice movement by stereo-photogrammetric means and the technique for it has also improved; algorithms and programs for machine processing of the data of multi-date surveys (ground and from aircraft) have been produced At this level of monitoring, it has been found that the retreat rate of most glaciers has slowed down and several glaciers are now in equilibrium. Several glaciers became active at the beginning of the 1970s and 1980s; this was accompanied by an increase in their height and forward movement. For example, activation of Kyukyurtlyu Glacier has been recorded (higher surface and increasing flow rate) which has caused the glacier to move forward 100 m. Surveys at an interval of 2 years recorded the beginning of the process of retreat of this glacier. Detailed monitoring is used to detect the mechanism of the dynamic processes and to study it on local representative sectors. On a glacier it may take the form of annual surveys of its tongue, which makes it possible to observe the processes of formation of moraines and glacio-fluvial relief. Studies may also be made of the mechanism of the movement of avalanches and landslides, deducing their quantitative characteristics and appraising the results of avalanches and landslides. Multi-date surveys of sectors of the slopes provide information about processes in the periglacial zone. At this level, regularly repeated ground stereo-photogrammetric surveys are the main means of observation. Glaciological remote-sensing monitoring provides a wealth of data for theoretical development in the field of glaciology. It makes it possible to forecast and produce warnings about hazardous processes and phenomena.

The results of multi-temporal aerospace imagery of the coast of the Baydaratskaya Bay (Kara Sea) interpretation are presented. In order to draw up a sketch map for the estimated zoning of the territory according to the construction conditions of the onshore sections of the Bovanenkovo-Ukhta gas pipeline, studies were carried out. The methods, consisting of 3 stages, was used: 1) sequential of aerial photographs and satellite images interpretation of different scales; 2) spatial comparison of the obtained interpretation results with the available cartographic materials of geotechnical surveys; 3) drawing up maps and sketch maps of various contents, including the final sketch map of the estimated zoning according to the degree of favorableness of the territory for the construction of gas pipelines. Landsat satellite images (1999–2000) with a resolution of 30 m, as well as aerial photographs of 1949–1950, scale 1:60 000, covering the southern part of the coast of the Baydaratskaya Bay were used for interpretation. The retreat of the gulf coasts, changes in the configuration of the coastline, river channels in their deltaic parts, changes in the size of thermokarst lakes have been discovered over the past 50 years in the course of analysis and interpretation of Earth remote sensing data. The amount of coastal retreat varies in different parts of the coast of the Baydaratskaya Bay from 30 to 90 m, i.e. the rate of retreat of the coastline is between 0.6 and 1.8 m / year has been established. The places of development of thermokarst and polygonal wedge ice, as well as active river erosion, have been identified by deciphering signs. At the third, final stage of the studies performed, based on the analysis of natural factors that determine the patterns of distribution of the studied hazardous processes and phenomena, a schematic assessment zoning of the studied territory was carried out according to the degree of its favorableness for the construction of onshore sections of the gas pipeline. Three types of areas: unfavorable, relatively unfavorable and favorable are noted on the sketch map

Mapping Iron Age field systemsAn assessment of the applicability of aerial photographyThere is little doubt that agriculture constituted the fundamental activity in prehistoric Denmark following its introduction 6000 years ago. Traces of cultivation are, however, almost solely preserved in the form of ard marks on surfaces sealed beneath barrows or layers of aeolian sand. Only one period in prehistory shows coherent traces revealing how field systems were formed and how they fitted into the landscape. During the course of the Late Bronze Age (1000-500 BC), a system of cultivation was introduced over large parts of NW Europe in which the individual fields or plots were separated from one another by low earthen banks and terrace edges or lynchets. These field systems could extend over several hundred hectares.These cultivation systems appear primarily to have been in use between 500 BC and AD 200. Research into prehistoric field systems has a long tradition extending all the way back to the 1920s in England, The Netherlands and Denmark, whereas in NW Germany and on Gotland work took place during the 1970s, with the Baltic Countries being involved in the 1990s. Early research was directed in particular towards mapping the field systems which, at that time, lay untouched in agriculturally marginal areas such as heath and woodland.In Denmark, Gudmund Hatt was a pioneer in this field. During the course of several campaigns, especially during the 1930s, he recorded 120 occurrences of field systems, primarily on the heaths of Northern and Western Jutland. These were published in 1949 in his major work Oldtidsagre (i.e. Prehistoric Fields). His work was continued by Viggo Nielsen who recorded 200 field systems in the forests of Zealand and Bornholm, largely between 1953 and 1963. In the former Aarhus county, the record has subsequently been augmented by a systematic reconnaissance of the forests which took place between 1988 and 1992. Subsequently, this led to the extensive investigations of field systems at Alstrup Krat near Mariager. As early as the 1920s, English researchers were aware of the fact that both ploughed-down and preserved field systems were visible on aerial photographs. However, the method was first applied in Denmark, The Netherlands and NW Germany in the 1970s, leading to a several-fold increase in the number known localities. In Denmark, P.H. Sørensen recorded 447 field systems in the former Viborg and North Jutland counties alone. P. H. Sørensen has published a series of articles dealing with various aspects of aerial photography in relation to ancient field systems. For example, the colour and origin of the various soil marks, the shape and size of the plots, different types of field systems and the relationship with soil type. He has also published several surveys of individual field systems. A significant problem with P.H. Sørensen’s work relates to the very few published plans showing the field systems and to the fact that these are based exclusively on a single series of aerial photographs.The main aim of this article is to demonstrate the potential for mapping field systems on the basis of not one but several series of aerial photographs. This is done through the detailed survey and mapping of three individual field systems and access to a series of data sources with respect to the interpretation of information contained in the aerial photographs. These comprise an interpretation of the origin of soil marks of banks and lynchets and an evaluation of the degree to which this interpretation is influenced by subjectivity. It is beyond the scope of this investigation to locate the field systems within a settlement and landscape context.Sources and study areaIn order to explore the problems and questions outlined above, three field systems were chosen in the central part of Himmerland: Skørbæk Hede, Gundersted and Store Binderup (fig. 1). This selection took place on the basis of an examination and assessment of almost all recorded field systems in Himmerland evident on several series of aerial photographs. These three field systems chosen are among those best preserved and also the most cohesive. Furthermore, all three have been mapped previously: Skørbæk Hede by Hatt on the basis of field survey, and the two others by P.H. Sørensen on the basis of aerial photographs. This provides the opportunity to evaluate any possible subjectivity in the procedure employed. Hatt makes a distinction between field boundary banks and lynchets. This opens up the possibility of evaluating how the two forms of boundary appear on aerial photographs. At Gundersted Hatt cut two sections through boundary banks. These, together with sections from other of Hatt’s excavations and more recent examples from the investigations at Alsing Krat, form the basis for an investigation of how soil marks arise and develop over time. In this investigation, use has also been made of historical maps in order to reveal the influence of historical cultivation on the presence/absence of soil marks. The earliest maps are from c. 1780. The primary source remains, however, series of vertical aerial photographs. Access to the latter has become considerably easier in recent years. A large proportion is now accessible via various web portals, and recently an overview became available of the contents of private and public archives. For the purposes of this investigation, use has been made of scanned contact copies of aerial photograph series from 1954, 1961 and 1967. From digital archives, use has been made of aerial photographs from 1979 and 1981 and the orthophoto maps from 2007 and 2008, respectively.Digitalisation and rectification of aerial photographsPreviously, mapping on the basis of aerial photographs was a laborious process involving tracing paper and the transfer of features to topographic maps. The introduction of GIS has, however, eased the process considerably and has also made it easy to compare various map themes such as soil-type, land-use, and digital finds databases. Before mapping can commence, the aerial photograph must be scanned, rectified and geo-referenced. rectification was carried out using the programme Airphoto, while geo-referencing and drawing in of the features were done in MapInfo. An example is shown in figure 2.Soil marks – how do they originate?In order to understand how the boundary banks and lynchets between plots appear as soil marks on the aerial photographs, it is necessary to examine how these boundaries were built up and also the influences to which they have been exposed from their creation and up until the time when they are visible on aerial photographs. Figures 3 and 4 show sections through two boundary banks at Gundersted These were carried out by Hatt at the beginning of the 1930s, just prior to the area coming under cultivation again and 20-25 years before the first aerial photographs revealed pale traces of boundary banks. As the area had not been cultivated since the Iron Age, the stratigraphy is the result of natural soil-formation processes: a podsol has been formed, comprising a heath mor layer uppermost, beneath this a bleached sand layer and an iron pan, and at the base the old cultivation layer and the topsoil core of the boundary bank, consisting of brown and grey sand. Ploughing of the boundary banks will, initially, not result in significant soil marks as the three uppermost layers are of equal thickness along the whole length of the section. A pale soil mark will, however, appear when the boundary bank has been levelled out and the plough begins to turn up material from the light topsoil core. This soil transport can in some instances continue for more than 70 years, but the soil marks will as a consequence also become wide and fragmented. This account of the processes leading to the appearance of the pale soil marks is completely different from the only other theory proposed in this respect, i.e. that of P.H. Sørensen. He describes a development involving three phases, beginning with the ploughing up of the bleached sand horizon which generates a pale soil-colour trace. Later in the development there is a shift to a dark trace, when the material in the topsoil core becomes ploughed up. In the final phase, the trace shifts again to a pale colour, when the plough begins to bring up the subsoil. However, these two sections show neither a bleached sand horizon nor a darker topsoil core. Furthermore, no colour changes have been observed at any of the localities. The fact that the boundary banks are apparent as pale soil marks is not due to ploughing up of the bleached sand layer but of the topsoil bank core. Ploughing down of the other boundary form, the terrace edge or lynchet, as shown in figure 5, will similarly result in the formation of a pale soil-colour trace through material being brought up from the pale topsoil core. P.H. Sørensen was also fully aware of this situation, and it can be confirmed by comparing Hatt’s map of the Skørbæk Hede site, where a distinction is made between boundary banks and lynchets, with the soil marks apparent on the aerial photograph series Basic Cover 1954 (fig. 6).Dark vegetation marks and pale erosion marksAlmost all the soil marks that form a basis for the mapping of the three field systems appear pale in relation to the surroundings. There are, however, occasional exceptions to this rule in the form of dark marks in areas of heather heathland and newly-ploughed heath. On the aerial photograph of Skørbæk Hede from 1954, a few dark marks can be seen directly south of Trenddalen (fig. 6) which correspond with the results of Hatt’s survey. These lie in an area which was cultivated between 1937 and 1954. In 1961, the area was taken out of cultivation and became covered with small trees. A corresponding phenomenon can be observed to the west of the settlement where the heather heathland was cultivated between 1954 and 1961 (fig. 7). These marks probably arise from the vegetation as a consequence of better growing conditions over the topsoil cores of the boundary banks. The fact that lynchets and boundary banks offer different growing conditions has been documented at Alstrup Krat where it could be seen that in several places anemones grew on the lynchets. Differences in the vegetation on the field surfaces and the boundary banks have also been observed on aerial photographs showing the scheduled examples of field systems at Lundby Hede and Øster Lem Hede.The final type of soil-colour trace to be dealt with here comprises the very pale patches that occur on both sides of Trenddalen at Skørbæk Hede and on the western margins of the field system at Gundersted. These could possibly be interpreted as ploughed-up deposits of aeolian sand, but this is not the case. By comparison with the topography and through stereoscopic viewing of the aerial photographs it becomes clear that these features are located on steeply sloping terrain and that they are due to ploughing up of the sandy subsoil. They become both larger and more pronounced with time as more and more subsoil sand is progressively eroded out due to ploughing (figs. 6, 7, 8 and 9).The influence of historic cultivation on soil marksThe fact that Hatt could still see boundary banks and lynchets in the landscape during his investigations in the 1930s was of course due to these areas not having been ploughed since they were abandoned at some time during the Iron Age. The Royal Danish Academy of Sciences and Letters’ conceptual map from the end of the 18th century shows that 30% of Himmerland was covered by heath, 42% was cultivated, 21% lay as meadow and bog and only 4% was covered by woodland (fig. 1). By comparing the identified field systems with the heath areas on the maps, an idea can be gained of the duration of cultivation and how it has influenced the soil marks. Correspondingly, by comparing plans showing soil marks with the cultivated area shown on the conceptual map, it is possible to investigate whether cultivation, presumably continuous here since the 12th century, has erased traces of field systems dating from the Early Iron Age. Plates I-III show combined plans of soil marks from boundary banks, lynchets and recorded barrows at the three localities. The ordnance maps from the 1880s have been chosen as a background, showing contour lines, land use and wetland areas, and the cultivated areas have been added from the conceptual map. At both Gundersted and Skørbæk Hede, there are clearly no soil marks in the areas marked as cultivated on the conceptual map. Conversely, the immediately adjacent heath areas show many coherent traces. On this basis, it must be assumed that the field systems from the Early Iron Age also once extended into areas shown as cultivated on the conceptual map but that the long-term cultivation has apparently erased any trace of them. It should, however, be mentioned that Lis Helles Olesen’s investigations in NW Jutland only reveal a slight preponderance of field systems located on the old heath areas, so there may well be regional differences.The original total extent of the field systems is of course difficult to assess, but the field system at Store Binderup provides an idea of the order of magnitude. This field system is apparent as a well-defined topographic unit surrounded by wetland areas; the latter are shown on the conceptual map to be completely covered by heath. The field system extends over c. 75% of the cultivable area. In order to examine the influence of modern cultivation on the clarity of the soil marks, plans showing traces of the boundary banks have been compared with a series of historical maps. In general, the soil marks at all three localities appear most clear in areas which were cultivated latest. Former heath areas completely lacking in soil marks have probably never been cultivated. The last 50 years of cultivation with large agricultural machinery has had a dramatic effect on the soil marks. On figures 7, 8 and 9, clear evidence of ploughing out can be seen, whereby the soil marks in several places increase from 5 to 9 m in width. The negative effect of long-term cultivation on soil marks documented here only applies to pale soil marks on sandy soils. A number of field systems are apparent as dark soil marks, the visibility of which does not appear to be affected to the same extent by long-term cultivation. These make up only 3% of those recorded by P.H. Sørensen, and no sections through boundary banks are available from any of these field systems.Comparison of maps produced by field survey and from aerial photographsEvery map expresses an interpretation of what has been observed. This also applies of course to both Hatt’s mapping of the field systems on the ground in the 1930s and the subsequent mapping conducted on the basis of aerial photographs. Quality and credibility are, however, increased considerably, if the features observed can be confirmed by several sources or several researchers, reducing the subjective aspect to a minimum.On figures 10 and 11, the author’s plan of Skørbæk Hede based on aerial photographs is compared with the results of Hatt’s field survey. There is no doubt whatsoever that the aerial photographs are better able to show the overall extent of the field system. Conversely, the resulting plan is less detailed than Hatt’s map. In a few cases, however, sub-divisions of the fields are seen on the aerial photographs which Hatt did not record in his survey (figs. 8-9). In order to investigate subjectivity in the interpretation of the aerial photographs, a comparison has been made between the author’s and P.H. Sørensen’s plans of the field systems at Gundersted and Store Binderup (figs. 12, 13 and 14). Good agreement can be seen in the interpretation of the soil marks apparent on the aerial photographs of both localities. This suggests that the subjective aspect of the interpretational process is not a major problem.Evaluation of the method’s range with respect to studies of the agrarian landscapeAerial photographs encompass a great research potential relative to studies of the arable landscape during the Late Bronze Age and Early Iron Age. They are the only source available with respect to mapping the morphology and extent of the field systems, with the exception of the few remains tangible which still exist in woodland and on heaths. Field systems are particularly important in a cultural-historical context because they constitute the sole example from prehistory of the appearance of a total integrated cultivation system and how it was adapted to the landscape.The information contained on the aerial photographs, particularly in the form of pale soil marks resulting from the exposure or ploughing-up of the topsoil core of the boundary banks and lynchets, is a credible source relative to the mapping of the morphology and extent of field systems. Comparison between the maps and plans produced by several researchers mapping does not give cause to perceive the interpretation of the information as the aerial photographs as being particularly subjective. On the contrary, very good agreement can be seen between these interpretations.In a mapping exercise, use should be made of a number of different series of vertical aerial photographs as this provides the most detailed picture of the morphology of the field systems.A very significant source of error has been identified which must be taken into account when mapping the extent of the field systems, i.e. cultivation during historical times. In areas that were cultivated prior to the enclosure movement, i.e. in the very great majority of cases presumably since the 12th century, it cannot be expected to find pale soil marks. Long-term cultivation and the consequent mixing of the upper soil layers have erased most traces of boundary banks and lynchets. Renewed cultivation within the last 100-150 years appears, conversely, only seems to have had a marginal effect on the occurrence of soil marks. As mentioned above there can, however, be marked regional differences on the influence of historical cultivation on the clarity and degree of preservation of the soil marks. This is an aspect it will be interesting to study in more detail in the future.Michael VinterMoesgård Museum

Abstract. There is a major need for a complete and detailed global glacier inventory that is freely available in a digital format (vector outlines with attribute data) for all kinds of glaciological assessments, e.g. sea level rise, hydro-power, run-off and natural hazards. However, such an inventory is not yet available and the uncertainties due to the missing data for related calculations are large. While the existing World Glacier Inventory offers tabular data that were compiled from aerial photography and maps during the 1960s to 1970s for about 72'000 glaciers, current efforts are being exerted within the framework of the Global Land Ice Measurements from Space (GLIMS) initiative to compile vector outlines from satellite data and combine them with digital elevation models (DEMs). At this point, inventory data from about 100'000 of the estimated 160'000 glaciers are available in the GLIMS database. Due to the now free availability of satellite data from the United States Geological Survey's archive and near global DEMs with appropriate spatial resolution, a globally complete and detailed glacier inventory appears viable. This contribution provides an overview of past and ongoing activities related to the creation of glacier inventory data from satellite sensors, along with the methods employed and the challenges encountered in different parts of the world.

Despite the variety of flight task preparation programs represented in the market and introduction of new standards of technical requirements in topographic aerial photography, the design issues of the latter are not worked out in detail; the criteria of pixel size selection on the ground are not defined. The necessity of considering all the input data i.e. customer requirements to the outcome product, characteristics of the used technical means of flight support, navigation and photographic equipment, the impact of external factors of the photographic environment was noted in the paper. Within the framework of the unified methodical approach to the choice of the pixel size in the design, the use of theoretical and physical similarity criteria is proposed. The method provides analyzing aerial photography’s all external and internal factors complex interaction and consideration of their affecting the result. Physical criteria, i.e. stability of flight, image quality of images, and depth of depicted high-altitude objects sharpness are considered in detail. The theoretical justification of determining the similarity coefficients is given. It analyzes the changes in coefficients depending on focal length, camera exposure parameters, etc. The method of taking into account physical factors and estimation of design accuracy is presented. The software implementation of the method is described. The practical example of multi-factor data analysis for selection of pixel size for designing large-scale aerial photography of built-up area is considered. The relevance of determining the coefficients directly in the course of aerial survey is shown.

Climate warming has become indisputable, and it is now crucial to increase our understanding of both the mechanisms and consequences of climate change. The Antarctic region is subjected to substantial changes, the trends of which have been recognized for several decades. In the South Shetland Islands, the most visible effect of climate change is progressive deglaciation. The following review focuses on past glaciological studies conducted on King George Island (KGI). The results of collected cryosphere element observations are discussed herein in a comprehensive manner. Our analysis showed that there is a lack of temporal as well as spatial continuity for studies on the basic mass balance parameters on the entire KGI ice dome and only Bellingshausen Dome has a relatively long history of data collection. The methodologies of past work, which have improved over time, are also discussed. When studying the glacier front fluctuations, the authors most frequently use a 1956 aerial photography as reference ice coverage. This was the case for seven papers, while other sources are seldomly mentioned. In other papers as many as 41 other sources were used, and therefore comparison to photos taken up to 60 years later can give misleading trends, as small glaciers may have both advanced and retreated in that time. In the case of glacial velocities there is also an apparent lack of consistency, as different glaciers were indicated as the fastest on KGI. Only Lange, Anna, Crystal, Eldred, and eastern part of Usher glaciers were determined by more than one author as the fastest. Additionally, there are gaps in the KGI Ground Penetrating Radar (GPR) survey area, which includes three ice domes: the Warszawa Icefield, the Krakow Icefield, and eastern part of King George Island. Ideas for further work on the topic are also suggested, allowing for easier access to data and thus contributing to a better understanding of glacier development mechanisms.

AbstractMany glaciers in Svalbard and in other glacierized areas of the world are known to surge. However, the time series of observations required to assess the duration of fast motion is very restricted. Data on active-phase duration in Svalbard come from aerial photographs, satellite imagery, field surveys and airborne reconnaissance. Evidence on surge duration is available for eight Svalbard ice masses varying from 3 to 1250 km2. Worldwide, active-phase duration is recorded for less than 50 glaciers. Few observations are available on high polar ice masses. The duration of the active phase is significantly longer for Svalbard glaciers than for surge-type glaciers in other areas from which data are available. In Svalbard, the active phase may last from 3 to 10 years. By contrast, a surge duration of 1–2 years is more typical of ice masses in northwest North America, Iceland and the Pamirs. Ice velocities during the protracted active phase on Svalbard glaciers are considerably lower than those for many surge-type glaciers in these other regions. Mass is transferred down-glacier more slowly but over a considerably longer period. Svalbard surge-type glaciers do not exhibit the very abrupt termination of the active phase, over periods of a few days, observed for several Alaskan glaciers. The duration of the active phase in Svalbard is not dependent on parameters related to glacier size. The quiescent phase is also relatively long (50–500 years) for Svalbard ice masses. Detailed field monitoring of changing basal conditions through the surge cycle is required from surge-type glaciers in Svalbard in order to explain the significantly longer length of the active phase for glaciers in the archipelago, which may also typify other high polar ice masses. The finding that surge behaviour, in the form of active-phase duration, shows systematic differences between different regions and their environments has important implications for understanding the processes responsible for glacier surges.

AbstractMany glaciers in Svalbard and in other glacierized areas of the world are known to surge. However, the time series of observations required to assess the duration of fast motion is very restricted. Data on active-phase duration in Svalbard come from aerial photographs, satellite imagery, field surveys and airborne reconnaissance. Evidence on surge duration is available for eight Svalbard ice masses varying from 3 to 1250 km2. Worldwide, active-phase duration is recorded for less than 50 glaciers. Few observations are available on high polar ice masses. The duration of the active phase is significantly longer for Svalbard glaciers than for surge-type glaciers in other areas from which data are available. In Svalbard, the active phase may last from 3 to 10 years. By contrast, a surge duration of 1–2 years is more typical of ice masses in northwest North America, Iceland and the Pamirs. Ice velocities during the protracted active phase on Svalbard glaciers are considerably lower than those for many surge-type glaciers in these other regions. Mass is transferred down-glacier more slowly but over a considerably longer period. Svalbard surge-type glaciers do not exhibit the very abrupt termination of the active phase, over periods of a few days, observed for several Alaskan glaciers. The duration of the active phase in Svalbard is not dependent on parameters related to glacier size. The quiescent phase is also relatively long (50–500 years) for Svalbard ice masses. Detailed field monitoring of changing basal conditions through the surge cycle is required from surge-type glaciers in Svalbard in order to explain the significantly longer length of the active phase for glaciers in the archipelago, which may also typify other high polar ice masses. The finding that surge behaviour, in the form of active-phase duration, shows systematic differences between different regions and their environments has important implications for understanding the processes responsible for glacier surges.

AbstractHigh-resolution ground-penetrating radar surveys at 50 MHz on the polythermal glaciers Hornbreen, Hambergbreen and several surrounding glaciers in southern Spitsbergen, Svalbard, are presented and interpreted. Accurate positioning was obtained using differential global positioning system (DGPS). Digital elevation models (DEMs) of the bedrock and surface were constructed. Comparison of DGPS data and surface DEMs with data from the topographic mappings from 1936 oblique stereoscopic aerial photographs and from Mission Russe in 1899–1901 shows that the Hornbreen and Hambergbreen surfaces are about 60–100 m thinner today in the upper part than at the beginning of the 20th century. Hornbreen has retreated by 13.5 km from the central part of the front, and Hambergbreen by 16 km. All the fronts of the nearby east-coast glaciers in this area have retreated. The bedrock DEM shows that the Hornbreen and Hambergbreen beds lie at –25 to 25 m a.s.l. The combination of sub-sea-level fronts and increasing steepness of the glaciers suggests that the low-lying glaciated valley filled by Hornbreen and Hambergbreen may become a partially inundated ice-free isthmus within perhaps 100 years.

Abstract. The number of studies of Little Ice Age (LIA) glacier fluctuations in southern South America has increased in recent years but is largely biased towards sites in the south Patagonian Andes. In this paper we present a detailed record of length and areal fluctuations of Glaciar Esperanza Norte (GEN) in the north Patagonian Andes of Argentina during the past four centuries. The GEN record was reconstructed through the dendro-geomorphological dating of moraines and the analysis of satellite imagery, aerial photographs and documentary material complemented with extensive field surveys. The maximum LIA extent at GEN was associated with an outer moraine dated to the mid 17th century. At least 19 subsequent readvances or standstills evidenced by morainic ridges were identified inside the most extensive LIA moraine. The dating and spacing of these moraines and the additional information available indicate that the ice front retreated much more rapidly during the 20th century than during earlier centuries. Comparison with the record of LIA fluctuations of Glaciar Frías, an ice mass of similar characteristics located 110 km to the north of GEN, shows a similar pattern of recession over the past 400 yr. Both glacier records have the peak LIA event occurring roughly during the same interval (early-mid 17th century) and show a minor readvance during the 1970s, but there are still a few discrepancies in the dating of some inner moraines. These differences may be due to local, specific factors or associated with the inherent uncertainties in the dating of the moraines. The chronologies of GEN and Frías are among the most detailed currently available in Patagonia, but a larger number of study sites is needed to develop robust, regionally representative glacier chronologies. Detailed glaciological, geomorphological and meteorological data are also needed to understand the glacier-climate relationships in this region and develop reliable paleoclimatic reconstructions.

Abstract. The number of studies of Little Ice Age (LIA) glacier fluctuations in Southern South America has increased in recent years but is largely biased towards sites in the South Patagonian Andes. In this paper we present a detailed record of length and areal fluctuations of Glaciar Esperanza Norte (GEN), in the North Patagonian Andes of Argentina, during the past four centuries. The GEN record was reconstructed through the dendro-geomorphological dating of moraines and the analysis of satellite imagery, aerial photographs and documentary material complemented with extensive field surveys. The maximum LIA extent at GEN was associated with an outer moraine dated to the mid 17th century. At least 19 subsequent readvances or standstills evidenced by morainic ridges were identified inside the most extensive LIA moraine. The dating and spacing of these moraines and the additional information available indicate that the ice front retreated much more rapidly during the 20th century than during earlier centuries. Comparison with the record of LIA fluctuations of Glaciar Frías, an ice mass of similar characteristics located 110 km to the north of GEN, shows a similar pattern of recession over the past 400 yr. Both glacier records have the peak LIA event occurring roughly during the same interval and show a minor readvance during the 1970s, but there are still a few discrepancies in the dating of some inner moraines. These differences may be due to local, specific factors or associated with the inherent uncertainties in the dating of the moraines. The chronologies of GEN and Frías are among the most detailed currently available in Patagonia, but a larger number of study sites is needed to develop robust, regionally representative glacier chronologies. Detailed glaciological, geomorphological and meteorological data are also needed to understand the glacier-climate relationships in this region and develop reliable paleoclimatic reconstructions.

Abstract. Five ground-based differential interferometric synthetic aperture radar (GB-DInSAR) surveys were conducted between 2005 and 2007 at the rock slope instability at Randa, Switzerland. Resultant displacement maps revealed, for the first time, the presence of an active basal rupture zone and a lateral release surface daylighting on the exposed 1991 failure scarp. Structures correlated with the boundaries of interferometric displacement domains were confirmed using a helicopter-based LiDAR DTM and oblique aerial photography. Former investigations at the site failed to conclusively detect these active release surfaces essential for kinematic and hazard analysis of the instability, although their existence had been hypothesized. The determination of the basal and lateral release planes also allowed a more accurate estimate of the currently unstable volume of 5.7±1.5 million m3. The displacement patterns reveal that two different kinematic behaviors dominate the instability, i.e. toppling above 2200 m and translational failure below. In the toppling part of the instability the areas with the highest GB-DInSAR displacements correspond to areas of enhanced micro-seismic activity. The observation of only few strongly active discontinuities daylighting on the 1991 failure surface points to a rather uniform movement in the lower portion of the instability, while most of the slip occurs along the basal rupture plane. Comparison of GB-DInSAR displacements with mapped discontinuities revealed correlations between displacement patterns and active structures, although spatial offsets occur as a result of the effective resolution of GB-DInSAR. Similarly, comparisons with measurements from total station surveys generally showed good agreement. Discrepancies arose in several cases due to local movement of blocks, the size of which could not be resolved using GB-DInSAR.

The erosion of old-growth forests in boreal managed landscapes is a major issue currently faced by forest managers; however, resolving this problem requires accurate surveys. The intention of our study was to determine if historic operational aerial forest surveys accurately identified boreal old-growth forests in Quebec, Canada. We first compared stand successional stages (even-aged vs. old-growth) in two aerial surveys performed in 1968 (preindustrial aerial survey) and 2007 (modern aerial survey) on the same 2200 km2 territory. Second, we evaluated the accuracy of the modern aerial survey by comparing its results with those of 74 field plots sampled in the study territory between 2014 and 2016. The two aerial surveys differed significantly; 80.8% of the undisturbed stands that were identified as “old-growth” in the preindustrial survey were classified as “even-aged” in the modern survey, and 60% of the stands identified as “old-growth” by field sampling were also erroneously identified as “even-aged” by the modern aerial survey. The scarcity of obvious old-growth attributes in boreal old-growth forests, as well as poorly adapted modern aerial survey criteria (i.e., criteria requiring high vertical stratification and significant changes in tree species composition along forest succession), were the main factors explaining these errors. It is therefore likely that most of Quebec’s boreal old-growth forests are currently not recognized as such in forest inventories, challenging the efficacy of sustainable forest management policies.

The Patagonian glaciers located in the southern part of the Andes between 46°30′S and 51°30′S are characterized by typical temperate conditions of heavy precipitation, rapid ice flows and high melting rates. During the austral summers of 1983–84 and 1985–86, field studies were made of the ice flow, heat balance and morphology of several glaciers in Patagonia. Coupled with aerial photographic surveys, these revealed that most glaciers had retreated extensively in the recent years, a maximum being 200 m a-1 at San Rafael Glacier from 1974 to 1986. The lower part of Soler Glacier had thinned by a rate of 5.2 m a-1 from 1983 to 1985.This paper presents three possible mechanisms to explain the large variation of temperate glaciers during the last decade, based on analyses of mass balance and dynamics of Patagonian glaciers:(1) The annual melting rate was estimated at about 10–15 m a-1 in water equivalent over the ablation area (from 350 to 1350 m a.s.l.) of Soler Glacier. Monthly mean air temperature in the coldest season (June through August) was estimated at about 0°–4°C near the termini of most glaciers in Patagonia. That temperature coincides with an air temperature which is critical for solid or liquid precipitation. The difference in the surface albedo, that is, 0.7–0.8 for new snow and 0.4–0.55 for bare ice (0.1–0.2 for debris-covered ice), results in different melting rates. Hence, a slight change in air temperature should cause an enhanced change in ice thickness by a positive feedback mechanism.(2) The flow velocity was measured or estimated and was found to change daily and seasonally by factors of 3 to 5 at Soler Glacier. The large flow velocity variation was attributed to difference in the basal sliding velocity. Consequently, a change in the amount of subglacial water or the structure of the basal water system should cause a large change in the ice flow, which in turn results in a retreat or an advance of the glacier-like “mini-surge”.(3) Frequent fluctuations of calving glaciers (e.g. San Rafael and Pio XI glaciers) have been much reported; however, information on the position of the grounding lines is very scarce. The advance or retreat of the glacier front may possibly have been affected by that of the floating terminus. The rate of calving from the ice tongue or spreading of ice shelves should mainly be controlled by the melting rate of ice in the water and by the mechanical properties of ice, and these factors are not directly related to climatic change or the surge phenomenon.

The Patagonian glaciers located in the southern part of the Andes between 46°30′S and 51°30′S are characterized by typical temperate conditions of heavy precipitation, rapid ice flows and high melting rates. During the austral summers of 1983–84 and 1985–86, field studies were made of the ice flow, heat balance and morphology of several glaciers in Patagonia. Coupled with aerial photographic surveys, these revealed that most glaciers had retreated extensively in the recent years, a maximum being 200 m a-1 at San Rafael Glacier from 1974 to 1986. The lower part of Soler Glacier had thinned by a rate of 5.2 m a-1 from 1983 to 1985. This paper presents three possible mechanisms to explain the large variation of temperate glaciers during the last decade, based on analyses of mass balance and dynamics of Patagonian glaciers: (1) The annual melting rate was estimated at about 10–15 m a-1 in water equivalent over the ablation area (from 350 to 1350 m a.s.l.) of Soler Glacier. Monthly mean air temperature in the coldest season (June through August) was estimated at about 0°–4°C near the termini of most glaciers in Patagonia. That temperature coincides with an air temperature which is critical for solid or liquid precipitation. The difference in the surface albedo, that is, 0.7–0.8 for new snow and 0.4–0.55 for bare ice (0.1–0.2 for debris-covered ice), results in different melting rates. Hence, a slight change in air temperature should cause an enhanced change in ice thickness by a positive feedback mechanism. (2) The flow velocity was measured or estimated and was found to change daily and seasonally by factors of 3 to 5 at Soler Glacier. The large flow velocity variation was attributed to difference in the basal sliding velocity. Consequently, a change in the amount of subglacial water or the structure of the basal water system should cause a large change in the ice flow, which in turn results in a retreat or an advance of the glacier-like “mini-surge”. (3) Frequent fluctuations of calving glaciers (e.g. San Rafael and Pio XI glaciers) have been much reported; however, information on the position of the grounding lines is very scarce. The advance or retreat of the glacier front may possibly have been affected by that of the floating terminus. The rate of calving from the ice tongue or spreading of ice shelves should mainly be controlled by the melting rate of ice in the water and by the mechanical properties of ice, and these factors are not directly related to climatic change or the surge phenomenon.

The aim of the work is to investigate the accuracy of the DEM of nearshore areas using UAV material. One of the important issues in hydrological flood modelling is the high accuracy of the DEM. In the case of a complex relief type, which is associated with meandering riverbeds, it is proposed to use UAV surveys to create a DEM. Hydrological modelling involves the following main steps: creation of high precision DEMs, determination of Manning coefficients to account for the influence of the underlying surface and determination of water level changes based on the water level graph derived from observations at hydrometeorological stations. This research presents the construction of a high-precision DEM, based on a UAV survey. For high-precision modeling, the fundamental issue is the consideration of vegetation in the nearshore areas and the choice of the optimal time period for the survey. The aim of the study is to develop a methodology for the construction of a high-precision DEM from UAV data, investigate the possibilities of eliminating the influence of vegetation on point marks using software methods, determine planned channel shifts and compare the accuracy of DEM construction for surveys conducted in June 2017 and in November 2021. The section at the transition from the mountainous to marshy-hilly part of the Dniester River near the town of Stary Sambir, with complex morphometric and hydrological characteristics of the channel and banks at the site of the complex meandering of the river in a rugged ravine area was the study object of this work. Results. It was found that for 4 years between two surveys, the planned displacements of some points are up to 25-31 meters. A priori estimation of coordinates determination by points from the GNSS-receiver was carried out, the accuracy of point coordinates determination is 2-3 cm. The a priori estimate of the accuracy of determining the coordinates of points from the input survey data is: for plan coordinates - 4-6 cm for two survey periods, the error in determining the marks of points for different values of the baseline - 21-31 cm. It has been established, that the program methods of accounting of influence of high vegetation do not give the possibility of its full accounting, the average square error, in places of such vegetation makes 0,64 m. Therefore, it is necessary to carry out UAV survey in the leafless period of the year, early spring or late autumn. Scientific novelty consists in the study of the possibility of constructing a high-precision DEM for different types of vegetation from materials obtained from UAVs. The results can be used for hydrological modeling of river channels with complex hydromorphological characteristics.

Nowadays, surveys using unmanned aerial vehicles is becoming popular. The resulting orthophotomap is the final product for creating digital plans and cardboard. The objectives of the study are to study the possibilities of obtaining orthophotomaps from survey materials using unmanned aerial vehicles based on the results of the experiment. The article describes various types of aerial photography. Some types of unmanned flying vehicles to conduct aerial photography for the purpose of monitoring, engineering surveys, inventory of agricultural land, and crop forecasts are considered. A description of aerial photography surveying is given on the example of the city of Dzerzhinsk, Minsk Region, which is performed taking into account the unmanned flying vehicles of GeoScan 201 and the Republican agricultural aero-geodesic unitary enterprise BelPSHAGI. A description of the GeoScan Planner software and basic pre-flight preparation is given. The stages of the preparatory work before the aerial photography, the creation of the planning and high-altitude geodetic justification, the implementation of aerial photography procedures, the steps of the aerial photograph anchorage procedure are considered. Agisoft Photoscan, which allows to get clouds of points, surfaces, 3D models and orthophotomaps using digital raster images are presented. The map of heights (DEM) of the terrain and the orthophotomap was made on the basis of a dense points cloud. According to the results of the research, a conclusion was made on the possibility of using aerial photography materials obtained using unmanned flying vehicles to get orthophotomaps of the required accuracy.

AbstractThis paper outlines selected remote sensing techniques and their application to civil engineering surveys.In BS 5930, emphasis has been placed on the interpretation of black and white aerial photography to provide information. However, other techniques such as true colour and false colour infrared photography, thermal infrared, radar and landsat satellite imagery may be useful in appropriate applications.

Digital oblique aerial camera (hereinafter called “oblique cameras”) is an assembly of medium format digital cameras capable of shooting digital aerial photographs in five directions i.e. nadir view and oblique views (forward and backward, left and right views) simultaneously and it is used for shooting digital aerial photographs efficiently for generating 3D models in a wide area. <br><br> For aerial photogrammetry of public survey in Japan, it is required to use large format cameras, like DMC and UltraCam series, to ensure aerial photogrammetric accuracy. <br><br> Although oblique cameras are intended to generate 3D models, digital aerial photographs in 5 directions taken with them should not be limited to 3D model production but they may also be allowed for digital mapping and photomaps of required public survey accuracy in Japan. <br><br> In order to verify the potency of using oblique cameras for aerial photogrammetry (simultaneous adjustment, digital mapping and photomaps), (1) a viewer was developed to interpret digital aerial photographs taken with oblique cameras, (2) digital aerial photographs were shot with an oblique camera owned by us, a Penta DigiCAM of IGI mbH, and (3) accuracy of 3D measurements was verified.

Digital oblique aerial camera (hereinafter called “oblique cameras”) is an assembly of medium format digital cameras capable of shooting digital aerial photographs in five directions i.e. nadir view and oblique views (forward and backward, left and right views) simultaneously and it is used for shooting digital aerial photographs efficiently for generating 3D models in a wide area. &lt;br&gt;&lt;br&gt; For aerial photogrammetry of public survey in Japan, it is required to use large format cameras, like DMC and UltraCam series, to ensure aerial photogrammetric accuracy. &lt;br&gt;&lt;br&gt; Although oblique cameras are intended to generate 3D models, digital aerial photographs in 5 directions taken with them should not be limited to 3D model production but they may also be allowed for digital mapping and photomaps of required public survey accuracy in Japan. &lt;br&gt;&lt;br&gt; In order to verify the potency of using oblique cameras for aerial photogrammetry (simultaneous adjustment, digital mapping and photomaps), (1) a viewer was developed to interpret digital aerial photographs taken with oblique cameras, (2) digital aerial photographs were shot with an oblique camera owned by us, a Penta DigiCAM of IGI mbH, and (3) accuracy of 3D measurements was verified.

This work describes the practical implementation of the method for digital noise suppression during processing images containing ice information to recognize automatically the contours of «ice-water» objects during aerial photography. Images containing ice information have special characteristic structural features related to noise, e.g.granularity, glare, ice crumbs. This makes difficult or even impossible to recognize automatically the contours of ice-water objects. It is known that the success of the application of edge recognition methods depends on how much image noise is reduced. The paper discusses the construction method for the management of noise. The method is based on the sequential application of the Haar wavelet transform denoising using thresholding, clustering by k-means method. For the subsequent automatic construction of ice floes contours the Sobel operator is applied.The aim of the work is to develop a method capable to process digital images effectively that contain ice information with strong digital noise. In this work we treated the images of one-year ice containing strong digital image noise in the form of granularity and in the form of ice crumbs. A description of the features of each of the steps of the proposed method and practical application is given.As a result, the method was developed for processing images of ice information containing digital noise in absolute value commensurate with the basic data. It was noted that the use of the k-means method expands the scope. The k-rare method allows more detailed processing of ice information and distinguishes not only the contours of ice-water objects, but also the contours of ice crumbs.The conclusion formulates the main advantages of the method and the possible application of the algorithm in the process of local exploration of the ice conditions of the Northern Sea Route channel using unmanned aerial vehicle for aerial photography. The usage of unmanned aerial vehicle for aerial photography will increase the frequency of weather forecast updates and predict the appearance of ice objects at the ship’s heading. That will allow us to select the safest and most economical efficient route along the Northern Sea Route.The authors have no competing interests.

At present, in Kuzbass, various methods of automation of plane surveys in open mining are used. In most cases, the choice of method depends on the material base of the enterprise and the professionalism of the performers. Typically, the work on the surveying automation consists in using electronic tachometers, which reduce time and simplify field and office work. However, the use of electronic tachometers remains the human factor and does not allow solving the problem of displaying the situation throughout the open pit at one physical moment of time. Aerial photography (AP) significantly increases the performance of plane surveys and makes it possible to most fully and reliably display the information about the surface and ensure the safety of fieldwork. The article presents a comparative analysis of the accuracy of constructing a digital terrain model obtained during aerial photography by AN-2 aircraft and instrumental survey performed with electronic tachometer Leica TS 06 plus, by example of surveying a trench of section № 1 at Olzherassky open pit in the Kemerovo region. The advantages and disadvantages of AP from an airplane and prospects of using AP from an unmanned aerial vehicle (UAV) are given.