Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 43-44). Also available on the World Wide Web.

An orthophoto map is made from a combination of different geospatial datasets such as relief, imagery, powerlines and annotation. These data sets are usually generated by different divisions within national mapping agencies. Often, when an orthophoto mapping project is to be undertaken, other functions within and outside the system, are actuated. Examples of such functions include; photogrammetric scanning, digital elevation capturing, aerial triangulation, ancillary data and imagery acquisition and map compilation. This research is underpinned by the hypothesis that different components that supply data required for generating orthophoto maps do not work as a coherent whole. This behaviour impacts negatively on the production of orthophoto maps as well as the quality of the end product and can have spill over effects on service delivery. In this research, systems analysis, client satisfaction survey and SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis are used as a collective set of tools to analyze an orthophoto mapping system (OMS) in order to mitigate this unwanted behaviour. The case of orthophoto map production at the Chief Directorate of Surveys and Mapping (CDSM) in South Africa is used. First, systems analysis, which uses the Data Flow Diagram (DFD) technique, is employed to depict the system‘s data stores, processes and data flows. This approach helps to show how the current system works thereby assisting to pin point areas that require improvement. After presenting the system ‘s processes, data stores and data flows, a client satisfaction survey, built on the criteria of; accuracy, completeness, correctness and accessibility of geospatial datasets, is conducted on one of the data stores – the Topographical Information System (TIS) database. Finally, a SWOT analysis is then done on the whole OMS to evaluate the internal and external environment under which the current system operates in. Gaps are identified and recommendations suggested. Although in this case, the recommendations are built based on the CDSM case study, it is believed they can benefit other OMS’s in similar operating conditions elsewhere. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2010. / Full text also available online. Scroll down for electronic link.

Thesis (M.A.)--Carleton University, 2002. / Includes bibliographical references (p. 129-148). Also available in electronic format on the Internet.

This thesis explores the potential of Neural Radiance Fields (NeRF) for generating orthophotos in forestry applications. Traditional orthophoto production methods, such as those implemented in Pix4D, require high image overlap and significant data collection. NeRF, a novel 3D scene reconstruction technique, shows potential for reducing these requirements by effectively reconstructing scenes with lower image overlaps. This study compares the orthophotos produced by NeRF and Pix4D using various degrees of image overlap, evaluating the results based on geometric accuracy, image quality, and robustness to data variations. The findings indicate that NeRF can produce orthophotos from low-overlap images with geometric accuracy comparable to orthophotos produced by Pix4D from high-overlap images, though with some trade-offs in image sharpness. These results suggest potential cost savings and operational efficiencies in forestry applications, providing a viable alternative to traditional photogrammetric techniques.

A produção de mosaicos fotográficos é uma atividade de apoio bastante importante em diversas áreas tais como a geração de mapas, o monitoramento ambiental e o gerenciamento agrícola. A fotogrametria, e em especial a aerofotogrametria, é a ciência que trata, entre outros tópicos, da geração de mosaicos através de procedimentos trabalhosos, o que torna sua manutenção uma tarefa difícil e de alto custo. O Projeto ARARA (Aeronaves de Reconhecimento Assistidas por Rádio e Autônomas) representa uma alternativa de baixo custo para a aquisição de fotografias aéreas. Câmeras digitais de pequeno formato a bordo das aeronaves permitem a obtenção automática das fotografias necessárias para a geração de mosaicos. Este trabalho propõe uma metodologia para a geração e a atualização de mosaicos compostos por fotografias aéreas oblíquas digitais e de pequeno formato, adquiridas com o auxílio das aeronaves do Projeto ARARA. As fotografias podem ser submetidas a procedimentos que associam técnicas de ortoretificação e processamento digital de imagens para corrigir suas distorções geométricas e radiométricas. A metodologia apresentada neste trabalho procura evitar a necessidade de pontos de controle no solo e focaliza a geração automática ou semi-automática dos mosaicos. Procedimentos automáticos têm o potencial de permitir a utilização de uma grande quantidade de fotografias de pequeno formato em substituição às fotografias normalmente utilizadas pela aerofotogrametria convencional. / The generation of photographic mosaics is an important activity in many areas such as map production, environment monitoring and agricultural management. Photogrammetry, and specially aero-photogrammetry, are the sciences that deal, among other subjects, with mosaic generation using time consuming procedures, making the maintenance and updating of photographic mosaics a difficult and high-cost task. The ARARA Project (Autonomous and Radio Assisted Reconaissance Aircrafts), presents a low cost alternative to acquire aerial photographs. An onboard, small format digital camera can take automatically the photographs used for the mosaic generation. This work proposes a methodology for mosaic generation and updating using oblique, digital, small format aerial photographs taken by ARARA aircraft. Photographs can be corrected both geometrically and radiometrically by orthorectification and digital image processing procedures. The methodology presented in this work avoids the use of ground control points, focusing on the automatic and semi-automatic mosaic generation. An automatic procedure make possible the use of a large number of small format photographs to replace the photographs normally used in conventional aerophotogrammetry.

A produção de mosaicos fotográficos é uma atividade de apoio bastante importante em diversas áreas tais como a geração de mapas, o monitoramento ambiental e o gerenciamento agrícola. A fotogrametria, e em especial a aerofotogrametria, é a ciência que trata, entre outros tópicos, da geração de mosaicos através de procedimentos trabalhosos, o que torna sua manutenção uma tarefa difícil e de alto custo. O Projeto ARARA (Aeronaves de Reconhecimento Assistidas por Rádio e Autônomas) representa uma alternativa de baixo custo para a aquisição de fotografias aéreas. Câmeras digitais de pequeno formato a bordo das aeronaves permitem a obtenção automática das fotografias necessárias para a geração de mosaicos. Este trabalho propõe uma metodologia para a geração e a atualização de mosaicos compostos por fotografias aéreas oblíquas digitais e de pequeno formato, adquiridas com o auxílio das aeronaves do Projeto ARARA. As fotografias podem ser submetidas a procedimentos que associam técnicas de ortoretificação e processamento digital de imagens para corrigir suas distorções geométricas e radiométricas. A metodologia apresentada neste trabalho procura evitar a necessidade de pontos de controle no solo e focaliza a geração automática ou semi-automática dos mosaicos. Procedimentos automáticos têm o potencial de permitir a utilização de uma grande quantidade de fotografias de pequeno formato em substituição às fotografias normalmente utilizadas pela aerofotogrametria convencional. / The generation of photographic mosaics is an important activity in many areas such as map production, environment monitoring and agricultural management. Photogrammetry, and specially aero-photogrammetry, are the sciences that deal, among other subjects, with mosaic generation using time consuming procedures, making the maintenance and updating of photographic mosaics a difficult and high-cost task. The ARARA Project (Autonomous and Radio Assisted Reconaissance Aircrafts), presents a low cost alternative to acquire aerial photographs. An onboard, small format digital camera can take automatically the photographs used for the mosaic generation. This work proposes a methodology for mosaic generation and updating using oblique, digital, small format aerial photographs taken by ARARA aircraft. Photographs can be corrected both geometrically and radiometrically by orthorectification and digital image processing procedures. The methodology presented in this work avoids the use of ground control points, focusing on the automatic and semi-automatic mosaic generation. An automatic procedure make possible the use of a large number of small format photographs to replace the photographs normally used in conventional aerophotogrammetry.

Indiana University-Purdue University Indianapolis (IUPUI) / The primary objective of this research involves mapping out and validating the existence of sub surface drainage tiles in a given cropland using Remote Sensing and GIS methodologies. The process is dependent on soil edge differentiation found in lighter versus darker IR reflectance values from tiled vs. untiled soils patches. Data is collected from various sources and a primary classifier is created using secondary field variables such as soil type, topography and land Use and land cover (LULC). The classifier mask reduces computational time and allows application of various filtering algorithms for detection of edges. The filtered image allows an efficient feature recognition platform allowing the tile drains to be better identified. User defined methods and natural vision based methodologies are also developed or adopted as novel techniques for edge detection. The generated results are validated with field data sets which were established using Ground Penetration Radar (GPR) studies. Overlay efficiency is calculated for each methodology along with omission and commission errors. This comparison yields adaptable and efficient edge detection techniques which can be used for similar areas allowing further development of the tile detection process.