A more general analysis is typically appropriate for determining regional trends over large areas. Selection of Imagery Multispectral satellite imagery such as Landsat TM has the advantage of providing data for a large area at a relatively low cost. In addition the multispectral capabilities mean that the data can be processed to enhance features such as subtle differences in vegetation that can be used to identify fractures. Landsat TM data's resolution of about 28 m is sufficient for most regional studies for exploration trends. Another advantage of these data sources is that stereopairs may be obtained.
Stereo interpretations are extremely useful when detailed fracture analysis is required.
Because fracture density analysis is used to evaluate geologic characteristics of particular locations, it is critical that the fractures be plotted on a spatially-accurate base map. Most satellite imagery can be orthorectified and used as a mapping base prior to picking fractures. The correlation between productivity and fracture density varies depending on the geologic regime. For many settings, the best production is directly in areas of high fracture density. An example from the eastern Powder River Basin is the comparison between the extent of production at the Clareton field and fracture density.