Academic literature on the topic 'Aerial photography in forestryUnited States'

Aim. The aim of the proposed research is to substantiate the scientific and practical significance of calculating centers of states and regions territories , to conduct a historical review of centrographic research in Ukraine and in the world in the context of evolution of their methodology, to establish geodetic coordinates of the set of points lying on the line of the land state border and coastlines along the seas, and to determine the center of dead weight of the territory of Ukraine as the center of gravity of the broken polygon formed by state territory contours (geodesic center of Ukraine). Methods. In calculating the geodesic center of Ukraine, the authors used a method (in their own interpretation) of determining the center of gravity of the territory, proposed by Jean-Georges Affholder and tested by him in establishing the center of Europe. Results. The history of centrographic research is more than 250 years old, but only in the last-half century they have acquired a proper scientific character, becoming a solid geodesic base. The main milestones in the formation of the centrographic dimension in context of determining the centers of a number of leading world countries and the evolution of research methods are presented. It is established that it is necessary to distinguish the geometric, geographical and geodesic centers of territories, which differ in method of definition and level of accuracy stipulated by calculations requirements. Each of the recognized centers of the territory of Ukraine has its own significance and justification. Scientific novelty. A historical review of definition of the territories centers in the world and in Ukraine has been made. A method of calculating the center of territory gravity of Ukraine as the center of a broken landfill formed by its contours, including the land state border and coastline, is proposed. The concept of "geodesic center" has been introduced to denote the center of territory gravity, which describes a polygonal, including irregular, figure. The location and exact coordinates of the geodesic center of Ukraine, located in the Novoukrayinsky district of Kirovohrad region, has been established. Practical significance . Specifying the location of territories centers is important in terms of optimizing location of manufacturing facilities and infrastructure, as well as potential tourism facilities. The methods used in calculating territories centers of Ukraine can be used not only in conducting similar studies for administrative regions, but also in newly created districts, united territorial communities, etc.

<p><strong>Abstract.</strong> Libraries, museums and archives were the original big geospatial information repositories that to this day house thousands to millions of resources containing research-quality geographic information. However, these print resources (and their digital surrogates), are not easily incorporated into the contemporary research process because they are not structured data that is required of web-mapping and geographic information system tools. Fortunately, contemporary big data tools and methods can help with the large-scale conversion of historic resources into structured datasets for mapping and spatial analysis.</p><p>Single frame historic aerial photographs captured originally on film (hereafter “photographs”), are some of the most ubiquitous and information-rich geographic information resources housed in libraries, museums and archives. Photographs authentically encoded information about past places and time-periods without the thematic focus and cartographic generalization of historic print maps. As such, they contain important information in nearly every category of base mapping (i.e. transportation networks, populated places etc.), that is useful to a broad spectrum of research projects and other applications. Photographs are also some of the most frustrating historic resources to use due to their very large map-scale (i.e. small geographic area), lack of reference information and often unknown metadata (i.e. index map, flight altitude, direction etc.).</p><p>The capture of aerial photographs in the contiguous United States (U.S.) became common in the 1920s and was formalized in government programs to systematically photograph the nation at regular time intervals beginning in the 1930s. Many of these photography programs continued until the 1990s meaning that there are approximately 70 years of “data” available for the U.S. that is currently underutilized due to inaccessibility and the challenges of converting photographs to structured data. Large collections of photographs include government (e.g. the U.S. Department of Agriculture Aerial Photography Field Office “The Vault” – over 10 million photographs), educational (e.g. the University of California Santa Barbara Library – approximately 2.5 million photographs), and an unknown number non-governmental organizations (e.g. numerous regional planning commissions and watershed conservation groups). Collectively these photography resources constitute an untapped big geospatial data resource.</p><p>U.S. government photography programs such as the National Agricultural Imagery Program continued and expanded in the digital age (i.e. post early 2000s), so that not only is there opportunity to extend spatial analyses back in time, but also to create seamless datasets that integrate with current and expected future government aerial photography campaigns. What is more, satellite imagery sensors have improved to the point that there is now overlap between satellite imagery and aerial photography in terms of many of their technical specifications (i.e. spatial resolution etc.). The remote capture of land surface imagery is expanding rapidly and with it are new opportunities to explore long-term land-change analyses that require historical datasets.</p><p>Manual methods to process photographs are well-known, but are too labour intensive to apply to entire photography collections. Academic research on methods to increase the discoverability of photographs and convert them to geospatial data at large-scale has to date been limited (although see the work of W. Karel et al.). This presentation details a semi-automated workflow to process historic aerial photographs from U.S. government sources and compares the workflow and results to existing methods and datasets. In a pilot test area of 94 photographs in the U.S. state of Pennsylvania, the workflow was found to be nearly 100-times more efficient than commonly employed alternatives while achieving greater horizontal positional accuracy. Results compared favourably to contemporary digital aerial photography data products, suggesting that they are well-suited for integration with contemporary datasets. Finally, initial results of the workflow were incorporated into several existing online discovery and sharing platforms that will be highlighted in this presentation. Early online usage statistics as well as direct interaction with users demonstrates the broad interest and high-impact of photographs and their derived products (i.e. structured geospatial data).</p>

AbstractGiant reed is an invasive weed throughout the southern half of the United States, with the densest stands growing along the coastal rivers of southern California and the Rio Grande in Texas. The objective of this study was to use aerial photography to map giant reed infestations and to estimate infested areas along the Texas–Mexico portion of the Rio Grande. Aerial color-infrared photographs were taken along the Rio Grande between Brownsville and El Paso, TX, in June and July 2002. Based on the aerial photographs and ground surveys, the portion of the river from San Ygnacio to Lajitas, which has a river length of 898 km (558 mi), was found to be infested with giant reed. To estimate infested areas along both sides of the river, 65 (13.5%) of the 480 aerial photographs taken between Lajitas and San Ygnacio were randomly selected. The aerial photographs were digitized, rectified to Google Earth imagery, and then classified using maximum-likelihood classification techniques. The infested areas on both sides of the river, as well as water area and river length, from each photographic image were determined. Based on the estimates from the 65 aerial photos, the ratio of giant reed area to water area and the ratio of giant reed area to river length were calculated. The total giant reed area along the Rio Grande between Lajitas and San Ygnacio was estimated to be 5,981 ha (14,779 ac) with 3,714 ha or 62% on the U.S. side and 2,267 ha or 38% on the Mexican side. This study provides the first accurate estimates of giant reed infestations along the Texas–Mexico portion of the Rio Grande and will be useful for both land owners and government agencies for the estimation of water usage and economic loss and for the management and control of giant reed.

This study created digital terrain models (DTMs) from historical aerial images using Structure from Motion (SfM) for a variety of image dates, resolutions, and photo scales. Accuracy assessments were performed on the SfM DTMs, and they were compared to the United States Geological Survey’s three-dimensional digital elevation program (3DEP) light detection and ranging (LiDAR) DTMs to evaluate geomorphic change thresholds based on vertical accuracy assessments and elevation change methodologies. The results of this study document a relationship between historical aerial photo scales and predicted vertical accuracy of the resultant DTMs. The results may be used to assess geomorphic change thresholds over multi-decadal timescales depending on spatial scale, resolution, and accuracy requirements. This study shows that if elevation changes of approximately ±1 m are to be mapped, historical aerial photography collected at 1:20,000 scale or larger would be required for comparison to contemporary LiDAR derived DTMs.

Oblique airborne photogrammetry is rapidly maturing and being offered by service providers as a good alternative or replacement of the more traditional vertical imagery and for very different applications (Fig.1). EuroSDR, representing European National Mapping Agencies (NMAs) and research organizations of most EU states, is following the development of oblique aerial cameras since 2013, when an ongoing activity was created to continuously update its members on the developments in this technology. Nowadays most European NMAs still rely on the traditional workflow based on vertical photography but changes are slowly taking place also at production level. Some NMAs have already run some tests internally to understand the potential for their needs whereas other agencies are discussing on the future role of this technology and how to possibly adapt their production pipelines. At the same time, some research institutions and academia demonstrated the potentialities of oblique aerial datasets to generate textured 3D city models or large building block models. The paper provides an overview of tests, best practices and considerations coming from the R&D community and from three European NMAs concerning the use of oblique aerial imagery.

Abstract. Groundwater and surface water interactions within riparian corridors impact the distribution of phreatophytes that tap into groundwater stores. The changes in canopy area of phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine the location of trees with pre-development and post-development aerial photography over the Ogallala Aquifer in the central plains of the United States. It was found that once the depth to groundwater becomes greater than about 3 m, tree populations decrease as depth to water increases. This subsequently limited the extent of phreatophytes to within 700 m of the river. It was also found that phreatophytes have a higher likelihood of growing on hydrologic soil groups with higher saturated hydraulic conductivity. Phreatophytes exist along portions of the Arkansas River corridor where significant decreases in groundwater occurred as long as alluvium exists to create perched conditions where trees survive dry periods. Significant decreases (more that 50%) in canopy cover exists along river segments where groundwater declined by more than 10 m, indicating areas with good hydraulic connectivity between surface water and groundwater. Thus, interpretation of changes in phreatophyte distribution using historical and recent aerial photography is important in delineating zones of enhanced recharge where aquifers might be effectively recharged through diversion of surface water runoff.

Low-cost methods to measure forest structure are needed to consistently and repeatedly inventory forest conditions over large areas. In this study we investigate low-cost pushbroom Digital Aerial Photography (DAP) to aid in the estimation of forest volume over large areas in Washington State (USA). We also examine the effects of plot location precision (low versus high) and Digital Terrain Model (DTM) resolution (1 m versus 10 m) on estimation performance. Estimation with DAP and post-stratification with high-precision plot locations and a 1 m DTM was 4 times as efficient (precision per number of plots) as estimation without remote sensing and 3 times as efficient when using low-precision plot locations and a 10 m DTM. These findings can contribute significantly to efforts to consistently estimate and map forest yield across entire states (or equivalent) or even nations. The broad-scale, high-resolution, and high-precision information provided by pushbroom DAP facilitates used by a wide variety of user types such a towns and cities, small private timber owners, fire prevention groups, Non-Governmental Organizations (NGOs), counties, and state and federal organizations.

Over the last decade, police departments in the United States and elsewhere began to adopt geographic information systems (GIS) technology, recognizing the advantages of a system that enables the inspection of crime patterns and spatial filtering and querying, as well as more sophisticated analyses. If GIS is seen as a “primary” innovation in law enforcement, refinements in both visualization and geographic precision can be considered a secondary wave. In a case study in Baltimore County, Maryland, aerial photography and global positioning systems (GPS) were introduced and evaluated in an effort to develop an understanding of the possible benefits and limitations of the technologies. Incident street addresses geocoded in the usual manner were compared to coordinates obtained from a GPS instrument accurate to within a meter. Analysis suggests that locational errors were greater for some crime categories than for others.