Dissertations / Theses on the topic 'Aerial photography in watershed management'

I developed a new methodology to produce an orthorectified mosaic and a vegetation database of Petersburg National Battlefield using mostly digital methods. Both the mosaic and the database meet National Map Accuracy Standards and proved considerably faster than traditional aerial photograph interpretation methods. I classified vegetation polygons to the formation level using the Nature Conservancy?s National Vegetation Classification System. Urban areas were classified using Mitchell?s Classification Scheme for Urban Forest Mapping with Small-Scale Aerial Photographs. This method reduced the production time by 2/3, compared to traditional methods. It also reduced the chance of user error because re-tracing of the linework is not required.

My method started with scanning 75 aerial color IR photos, provided by Petersburg National Battlefield, at 600 dpi. Erdas Imagine was used to rectify the images using United States Geological Service (USGS) Digital Elevation Models (DEM) and black and white USGS Digital Orthophoto Quarter Quadrangles (DOQQ) as reference. The images were then mosaiced to create a seamless color infrared orthorectified basemap of the park. The vegetation polygons were drawn onscreen using ArcMap from Environmental Systems Research Institute, Inc. (ESRI) with the color, orthorectified mosaic as a background image. Stereo pairs of the aerial photos were referenced as needed for clarification of the vegetation. I used a minimum mapping unit (mmu) of 0.2 hectares, which exceeds guidelines defined by the United States Geological Survey ? National Park Service Vegetation Mapping Program. This methodology is easily learned quickly and has already been applied to several other studies.

The production of an orthorectified mosaic, created during the process, from the aerial photographs greatly increases the value of the photographs at little additional cost to the user. The orthorectified basemap can then be used as a backdrop for existing data layers or it can be used to create new GIS data layers. I used a minimum mapping unit (mmu) of 0.2 hectare, which exceeds guidelines defined by the United States Geological Survey-National Park Service Vegetation Mapping Program

Traditionally, vegetation polygons are delineated on acetate for each photograph. The linework on the acetates is then transferred to a basemap using a zoom transfer scope or other transfer instrument. The linework is traced again to digitize it for use in a GIS program. This process is time consuming, and the linework is drawn three times. The redundant tracing increases the chance of user error. My new methodology requires that polygons be delineated only once. I wanted to avoid using the zoom transfer scope and to avoid the redundant linework.

A total of 228 polygons were delineated over 20 separate vegetation and land cover classes with an overall thematic accuracy of 87.42% and a Kappa of .8545. Positional accuracy was very good with a RMSE of 1.62 meters in the x direction and 2.81 meters in the y direction. The Kappa and RMSE values compare favorably with accuracies obtained using traditional vegetation mapping methods.

The coastal zone is a highly dynamic entity both spatially and temporally and when shoreline changes (and in particular retreat) occur on a hmnan time-scale, measurement of the rate of change becomes a pressing issue. This dynamism presents an excellent scenario for monitoring change using remote sensing techniques, and in the case of coastal sand dunes, where the requirement is to measure small scale changes such as erosion or accretion in the region of 10 or 20 m, aerial photography is the preferred source of remotely sensed data. The rapid developments in digital camera technology and real time satellite differential Global Positioning Systems have yielded new opportunities for mapping and monitoring environmental change when used with image processing and mapping software and state-of-the-art digital photogrammetric workstations. Despite the progress in digital technologies, however, there is still considerable lack of awareness on the part of potential users, and it is in response to this that the processing chain for data collection through to orthophoto production described here has been developed. This study explores the major issues that affect quality, mission logistics and cost and will demonstrate the methodology and application of digital techniques for producing georectified imagery and contoured orthophoto maps of coastal environments. This will be achieved through a series of case studies of dynamic dune environments in south-west England and France. Digital imagery was captured using a colour infrared Aerial Digital Photographic System and ground control was collected using differential Global Positioning Systems. This study seeks to assess the application of this imagery to coastal dune monitoring, putting these new techniques within the grasp of coastal dune managers, enabling them to make use of digital imagery captured to different specifications depending on the accuracy requirement of the end product. The results indicate that this type of imagery and the techniques used can provide the dune manager with information which would otherwise be too costly or time consuming to acquire. 2D rectification of the imagery provided maps of dune retreat and accretion with errors in the region of± 1.5m, and rectification to a higher order using 3D photogrammetric correction provided 1 :5000 contoured orthophotographs with mean xy errors in the region of 2. 5 m and mean elevation errors in the region of 1.5m.

Despite the explosion of popularity of UASs, and the recognition that such systems must find a way to safely operate alongside manned aviation, a literature review by this author as well as interviews with three commercial aerial photography companies in Tampa Bay, Florida, indicate that regulatory restrictions are still the greatest obstacle to law abiding commercial UAS operators. It can take six to eight months with a backlog of 12,000 waiver applications to get either a Part 333 or Part 107 exemption, which grants FAA permission for a commercial operator to fly a UAS inside controlled airspace (Gardner, 2018). A manned pilot can file a flight plan and hover a helicopter over the same area in just a few hours. The purpose of this research was to determine what industry experts perceive the future of UAS regulations hold, and how the industry will be impacted in both the short term of 5 years and less, and long-term of 5 years or more. UAS industry expert interviews were conducted in the “reflection of the meaning”, semi-structured style, with each interviewee given the latitude to discuss topics as they came to mind. A preset approved bank of questions helped to guide the interview, but in many cases as experts in the field, the interviewees naturally discussed the topics covered in the preset questions and the interview adapted to avoid unnecessary repetition. One interview was conducted in-person, but the rest were via phone calls due to geographical separation.

Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains x, 128 p. : ill. (some col.), maps (some col.) Vita. Includes abstract. Includes bibliographical references (p. 116-121).

Thesis (MSc)--University of Stellenbosch, 2005.
ENGLISH ABSTRACT: Invasive alien trees, especially Acacia species, are a great threat to biodiversity in South African rivers. The national Working for Water Programme is addressing the alien problem by removing alien trees from river margins. The concern is that this may be creating even further disturbance by affecting water quality and habitats. In particular, how is this affecting rare and endemic species? Benthic macro invertebrates and aerial odonates were assessed along five Western Cape rivers in alien-invaded, cleared and natural sites between December and March. The aim was to assess the effect of both alien invasion and alien clearing on aquatic invertebrates. Odonata, being easily sampled, were also assessed as they are severely affected by the lack of understorey plants in shaded, alien-invaded sites. Odonata and benthic macroinvertebrates were treated as two separate studies and no attempt was made to correlate the results obtained from both studies. SASS5, a qualitative, rapid bioassessment technique, based on the sensitivity of the families present, was used as a measure of river health and, indirectly, of water quality. SASS indicated a decline in water quality conditions after alien clearing, a likely response to the greater insolation as well as erosion of cleared banks, resulting in elevated temperatures and suspended solids and lowered oxygen levels. Community responses to alien disturbance and other environmental factors were analysed using PRIMER and CANOCO software. Assemblages of Odonata were found to provide a rapid, cost-effective means of assessment and monitoring. Potential indicator and detector species were also identified using the lndicator Value method. Assemblage patterns of aquatic invertebrates, however, were dominated by between-river and seasonal effects. Therefore, while SASS detected overall changes in river health, without identifying the cause, potential aquatic detector taxa were identified that may be useful for linking general disturbance to alien invasion or clearing. All indicator and detector taxa identified in both studies can be used for long-term monitoring and for identifying biodiverse areas for clearing or protection. In both studies, sensitive, endemic taxa were lost after clearing, being replaced by more tolerant, widespread taxa. Recovery of the biota appears to follow the recovery succession of the vegetation, with most sensitive or endemic taxa only appearing after the recovery of indigenous plants. A number of recommendations are made regarding the restoration of both water quality (particularly with respect to shade and soil erosion) and biotope availability (particularly in terms of the recultivation of indigenous plants) in order to achieve biodiversity objectives. The role of catchment management, prioritisation procedures and long-term monitoring are also discussed.
AFRIKAANSE OPSOMMING: Uitheemse, indringerbome, veral Acacia spesies, is 'n groot bedreiging vir biodiversiteit in Suid- Afrikaanse riviere. Die nasionale Werk vir Water-projek spreek hierdie probleem aan deur uitheemse bome van rivieroewers te verwyder. Die kommer is dat water kwaliteit en habitatte sodoende verder versteur kan word. Byvoorbeeld, hoe word endemiese en bedreigde spesies geraak? Akwatiese makroinvertebrate en volwasse Odonata in vyf Wes-Kaapse riviere is tussen Desember en Maart bestudeer en gemonster in natuurlike gebiede, in gebiede waar indringerbome teenwoordig is, en in gebiede waar hulle verwyder is. Die doel was om die effek van indringerverwante impakte op akwatiese invertebrate vas te stel. Odonata is ook bestudeer omdat hulle maklik gemonster kan word en omdat hulle ernstig geraak word deur indringers. Die uitheemse plantegroei oorskadu die oewers en verhoed die groei van inheemse oewerplante. Die bentiese makro-invertebrate en Odonata is as twee aparte studies behandel en geen poging is gemaak om die resultate van die twee te vergelyk nie. SASSS, 'n kwalitatiewe, bioasseseringsmetode wat op die sensitiwiteit van die aanwesige families baseer word, is gebruik om waterkwaliteit op 'n indirekte manier te bepaal. SASS het aangedui dat daar 'n afname in waterkwaliteit is nadat indringerplante verwyder is. Dit is moontlik as 'n gevolg van groter blootstelling aan sonskyn en erosie van rivieroewers wat veroorsaak dat temperature en die hoeveelheid gesuspendeerde materiaal verhoog word, en dat suurstof konsentrasies verminder word. Die gevolge van indringerplante en ander omgewingsfaktore op akwatiese gemeenskappe is met PRlMER en CANOCO sagteware ontleed. Groepering van Odonata kan gebruik word om op 'n maklike en koste-effektiewe manier om die impak van indringerplante en hul verwydering te bepaal en te monitor. Aanwyserspesies is ook deur middel van die 'Indicator Value' metode geïdentifiseer. Die verspreidingspatrone van invertebraatspesies word deur geografiese en seisoenale effekte oorheers. Dus, terwyl SASS veranderinge in waterkwaliteit kan aantoon, sonder om die oorsaak daarvan te identifiseer, kan aanwyserspesies gebruik word om meer spesifieke impakte deur indringerplantegroei, of indringerverwydering, te bepaal en te monitor. Hulle kan ook gebruik word om gebiede met hoë biodiversiteit vir bewaring of indringerverwydering te identifiseer. Beide studies dui aan dat sensitiewe en endemiese taksa na indringerverwydering verlore gaan, en vervang word met meer geharde, wydverspreide taksa. Herstel van die biota volg op die herstel van die plant gemeenskappe, en die mees sensitiewe of endemiese taksa herstel eers nadat die inheemse plantegroei herstel het. 'n Aantal aanbevelings in verband met die restorasie van waterkwaliteit (veral in terme van die hoeveelheid skaduwee en erosie) en die beskikbaarheid van biotope (veral in terme van inheemse plante) om biodiversiteitsdoelwitte te bereik word gemaak. Die rol van opvanggebied bestuur, voorrang prosedures en lang termyn monitering word ook bespreek.

Leaf area index (LAI) provides forestry information that is important for regional scale ecological models and in studies of global change. This research examines the effects of mountainous terrain on the radiometric properties of multispectral CASI imagery in estimating ground-based optical measurements of LAI, obtained using the TRAC and LAI- 2000 systems. Field and image data were acquired summer 1998 in Kananaskis, Alberta, Canada. To account for the influence of terrain a new modified approach using the Li and Strahler Geometric Optical Mutual Shadowing (GOMS) model in 'multiple forward mode' (MFM) was developed. This new methodology was evaluated against four traditional radiometric corrections used in comination with spectral mixture analysis (SMA) and NDVI. The MFM approach provided the best overall predictions of LAI measured with ground-based optical instruments, followed by terrain normalized SMA, SMA without terrain normalization and NDVI.
xiv, 151 leaves : ill. (some col.), map ; 29 cm.

The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that: • Post-fire patterns of soil WR were highly correlated to pre-fire P-J woodland canopy structure. Critical soil WR levels occurred under burned tree canopies while sub-critical WR extended out to approximately two times the canopy radius. At sites where critical soil WR was present, infiltration rate, soil moisture, and vegetation cover were significantly less than at non-hydrophobic sites. These parameters were also reduced in soils with subcritical WR relative to non-hydrophobic soils (albeit to a lesser extent). Aerial photography coupled with feature extraction software and geographic information systems (GIS) proved to be an effective tool for mapping P-J cover and density, and for scaling-up field surveys of soil WR to the fire boundary scale. • Soil WR impairs seed germination and seedling establishment by decreasing soil moisture availability by reducing infiltration, decreasing soil moisture storage capacity, and disconnecting soil surface layers from underlying moisture reserves. Consequently, soil WR appears to be acting as a temporal ecological threshold by impairing establishment of desired species within the first few years after a fire. • Wetting agents can significantly improve ecohydrologic properties required for plant growth by overcoming soil WR; thus, increasing the amount and duration of available water for seed germination and seedling establishment. Success of this technology appears to be the result of the wetting agent increasing soil moisture amount and availability by 1) improving soil infiltration and water holding capacity; and 2) allowing seedling roots to connect to underling soil moisture reserves.

Thesis (M.Sc.)--University of Manitoba, 2006.
A thesis submitted to the Faculty of Graduate Studies in partial fulfillment of the requirements for the degree of Master of Science, Department of Soil Science. Includes bibliographical references.

L'objet de cette recherche est de tenter de caracteriser les mangroves des regions equatoriales humides sur le terrain et a partir d'enregistrements spatiaux. Dans la premiere partie, une synthese biogeographique sur les peuplements de paletuviers permet de faire apparaitre et de comprendre les variations des types de mangroves et de situer les mangroves indonesiennes dans un contexte plus general. La deuxieme partie represente une etude sur les mangroves du golfe de bone a sulawesi (indonesie)

Thesis (MTech. degree in Nature Conservation.)--Tshwane University of Technology, 2011.
Effective management and conservation of wildlife populations requires reliable estimates of population size, which are however usually difficult and costly to obtain. This study investigated the efficiency of two aerial counting techniques used in estimating wildlife populations, namely systematic reconnaissance flights and aerial distance sampling. In Tanzania systematic reconnaissance flights has long been the method of choice for aerial surveys, but aerial distance sampling potentially offers a more statistically robust sampling method. These two methods where compared to evaluate their all-round effectiveness for survey objectives in Tanzania. The study further assessed the impact of sampling designs and intensities on estimates of population parameters.

This study used a comparison of one hundred and forty-eight historical (1888-1913) and current (2008-2014) oblique photographs from thirty-two stations to identify land cover changes that have occurred in portions of the Bow and Elbow valleys as well as surrounding Kananaskis Country region. Implications of these changes for flooding and flood management were explored. Forest cover was found to have drastically increased over the past century, particularly in the Bow valley, as did areas of direct human development. In the same time period, grasslands increased in the Elbow valley but decreased in the Bow, while regenerating areas decreased uniformly throughout both valleys. An analysis of pre (2008)-and-post (2014) flood conditions demonstrated no change in coniferous forest cover in both valleys over the 6-year period, but uncovered a decline of 20% in the Elbow and 3% in the Bow in the broadleaf/mixedwood category. The Elbow’s channel zone was larger in 2014 compared to 2008, whereas the extent of the Bow’s channel zone remained constant. However, both the Bow and Elbow’s bare exposed bars increased substantially, most likely as a result of the 2013 flood. The major source of water flows that contributed to the 2013 flood event originated in high elevation rock and scree areas, which, unlike floodplains, are elements of the watershed that cannot be manipulated over time. It is now recognized that forest cover should act as a buffer to floods. Nevertheless, the 2013 flood event occurred despite the massive buffering effect of a huge increase in older forest stands across the study area. The final discussion includes recommendations for improving flood management in the area.
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