Basil G. Savitsky
THIS chapter provides a general background on the utilization of satellite imagery in tropical habitat mapping. The introductory section covers basic concepts in image analysis that are prerequisite to the content covered in the balance of the chapter. The second section provides a review of the literature on the habitat mapping capability of a variety of sensor systems. The third section covers the utility of satellite imagery in national and regional conservation mapping efforts in the tropics.
Remotely sensed data include a variety of data sources that are defined from the range of the spectrum of electromagnetic radiation. Aerial photography is used to capture reflective signals from the visible and near-infrared portion of the spectrum. Most digital scanners operate in similar portions of the spectrum. Thermal and radar sensor systems are sensitive to a different portion of the energy spectrum.
Remotely sensed data provide an operational GIS with timely and synoptic data. Image analysis techniques are commonly utilized to perform regional vegetation mapping and to update existing vegetation maps.
The utility of a sensor system for the detection of surface phenomena must be assessed along four dimensions: spatial resolution (area or size of feature that can be identified), spectral resolution (number and width of electromagnetic bands for which data are collected), radiometric resolution (detector sensitivity to various levels of incoming energy), and temporal resolution (frequency of satellite overpass) (Jensen 1995). The four satellite sensors that are addressed in