Academic literature on the topic 'Multispectral aerial videography'

Multispectral aerial videography was used to reproduce the jurisdictional delineation of wetland area of approximately 50 hectares in Davis County, Utah Imagery from the system consisted of three-band composite with wavelengths covering 550 nm (±10 nm), 650 nm (±10 nm), and 850 nm (±10 nm). The site was overflown at three different flight dates during the 1992 growing season (June 2, July 22, October 1). Imagery resolution varied from 0.56 m to 0.81 m. Mosaiced images were analyzed with a Supervised clustering/maximum likelihood classifier, ISODATA clustering/Euclidan classifier, statistical clustering/maximum likelihood classifier, and fuzzy c-means clustering. Overall accuracies for wetland/upland designations as compared to ground truth data varied from 60% to 75%. The ISODATA method was the poorest performer for all dates and both of two accuracy testing techniques. Supervised clustering and statistical clustering were comparable with a slight edge in accuracy to the supervised clustering. The best all-round performer was the fuzzy c-means algorithm in terms of time spent and accuracy.

A referida pesquisa tem como finalidade usar ferramentas de geotecnologias para mapear a distribuição espacial do campo térmico da cidade de Piracicaba, SP e comparar os diferentes tipos de superfícies urbanas. Foram feitas coletas de temperatura em 3 áreas distintas, em determinados horários, na estação do verão e inverno. Nesses pontos de coleta de temperatura foram criados polígonos circulares e por meio desses polígonos circulares foram retirados das imagens de alta resolução da videografia aérea multiespectral, utilizando a técnica de classificação supervisionada foram separados as porcentagens dos diferentes tipos das superfícies urbanas. Foram feitas comparações com imagens térmicas, e correlacionadas com pixels retirados do NDVI (Índice de Vegetação por Diferença Normalizada) das imagens multiespectrais da videografia aérea multiespectral, os resultados obtidos do R2=0,68. Outras comparações foram realizadas com as temperaturas coletadas e com cenas da banda 6 do Satélite Landsat 5. Para transformação das cenas, foi utilizado o algoritmo de transformação do software IDRISI 3.2. Foi possível obter mapas temáticos com valores da temperatura radiante da superfície urbana da cidade de Piracicaba. Os resultados obtidos pela comparação entre as classes de cobertura, copa de árvore e a temperatura foram satisfatórios obtendo-se um R2 de 0,56 para polígonos circulares de 50 metros, outros resultados como lago/lagoa o R2 foi 0,72 e para sombra 0,24. Com a evolução dos recursos de geotecnologia, sensoriamento remoto, sistema de informações geográficas, informações mais detalhadas serão obtidas do tecido urbano.
This research aims to use tools to map the geo-spatial distribution of thermal field in Piracicaba, SP, and compare the different types of urban surfaces. Samples were performed in temperature in 3 different areas, at certain times, in the summer season and winter. These collection points were set up temperature circular polygons and polygons through these circulars were derived from images of high resolution multispectral aerial videography, using the technique of supervised classification were separated from the percentages of different types of urban surfaces. Comparisons were made with thermal imaging and correlated with pixels taken from NDVI (Normalized Difference Vegetation Index) the multispectral images of multispectral aerial videography, the results of R2 = 0,68. Other comparisons were made with the temperatures collected and scenes of the band 6 of Landsat 5 (TM). For processing the scenes, we used the algorithm processing software IDRISI 3.2. It was possible to obtain thematic maps with radiant values temperature of the surface of the town of Piracicaba. The results obtained by comparing the classes of coverage, and canopy temperature were adequate to yield an R2 of 0,56 for circular polygons of 50 meters, other results such as lake/pond R2 was 0,72 and for shade 0,24. With the development of resources of geotechnology, remote sensing, geographic information system, more detailed information will be obtained from the urban fabric.