A Comparison of Aerial Photography, Landsat TM and SPOT Satellite Imagery

A study was done on the tropical wetland environments of northern Australia; population growth and environmental problems are encroaching and threatening the wetlands. Because of the remoteness and fragility of the area, remote sensing was an appealing method for obtaining information about the land. The purpose of the study was to investigate the utility of image data sets to see which type of image produced the best resolution for mapping the environment.

Method:
1.) In the study, Landsat, TM (satellite images) , SPOT XS and PAN (remote sensing satellites) and large-scale, true-color aerial photography were evaluated for mapping the vegetation.

2.) Five sample points were placed at 1km intervals. Each point was labeled and information about the location was recorded. To ensure the correct cover types were recorded, both photographic and written records were collected at each site. This procedure provided 12 observations per sample point and a total sample size of 240 observations for the entire swamp.

3.) Landsat, TM, SPOT, and large-scale photography was used for each location.

4.) Images were evaluated.

Results:
The study concluded that aerial photography was superior to satellite imagery for detailed mapping of vegetation environment studied.

The results suggest that either Landsat TM or SPOT XS imagery is adequate for mapping these generalized land cover classes. But the resolution needed for the classification of the vegetation was acquired through the aerial imagery. When comparing the two satellite imagery data sets, the broader spectral range of the Landsat TM data appeared to more than compensate for the superior spatial resolution of the SPOT imagery.

The researchers note that the most useful technique will depend on the application and is closely related to the physical characteristics of the features being mapped.

Study can be accessed through EBSCOhost:
Vegetation mapping of a tropical freshwater swamp in the Northern Territory, Australia: a comparison of aerial photography, Landsat TM and SPOT satellite imagery by K. R. HARVEY and G. J. E. HILL