This capability has not been previously possible in any globally consistent fashion due to wide variations in the information content, timeframe, accuracy, and availability of data, particularly in the developing regions of the world. Image stratification at the local and regional level serves to direct field data collection efforts to areas where they are most appropriate. Social scientists can use the geographical distribution of anthropogenically induced land surface conditions or other physical land characteristics to direct their acquisition of primary social science data and to assist the extrapolation of results. Thus, local and regional research studies will be optimally located in their evaluation of selected human activities. If the methodologies of local and regional studies are coordinated on a global scale, the results will be more conducive to global comparison and aggregation.
Satellite images can aid the physical acquisition of field data in several ways.
Satellite images have also been shown to facilitate the field survey interview process by serving as a visual reference when interviewing knowledgeable individuals about location and size of activities, and for checking the credibility of interview responses from indigenous persons. Figure 2 illustrates a synoptic view of forest alteration activities in Bolivia. Figure 3 illustrates the great detail that can be preserved in extreme enlargements of high resolution satellite images, making them useful as image maps for field survey interview work. Perhaps most importantly, the synoptic overview of landscape conditions at the local and regional level provided by satellite images can be used as a common frame of reference to facilitate identifying natural science data variables for subsequent joint analysis with social science data. Stratification of regions according to these joint considerations will create distinct areas in which to acquire information about human activities and the ecophysical context in which they occur.