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Current lineament mapping from satellite imagery is possibly limited by the time of satellite overpass and the resultant sun azimuth and elevation angles. The use of plastic topographic raised-relief maps provides a method of lineament mapping using a wide selection of lighting positions. A comparison of lineaments mapped from the two media has been made, including general orientation, orientation relative to sun azimuth, and orientations in which length is maximized. It has been determined that the lineaments are sufficiently similar to permit the use of relief-map photos as a viable alternative to satellite imagery. These photos can then be used to study the effect of satellite overpass time in lineament mapping.
Simulated overpass times were represented in raised relief map photos. Overall, maximum lineament detection occurs at a relative sun azimuth range of 10 to 30°, and at sun elevation angles of 30 to 40°. In individual images, the maximization by relative azimuth is modified by the presence of a major lineament trend.
An effort to predict optimum overpass time indicates that no one specific overpass will provide adequate detection of an entire collection of lineaments in a region. However, if an operator is interested in lineaments trending at a specific orientation, an overpass time can be recommended that will provide the desired sun elevation and azimuth angles. Relief maps of the Appalachian Plateau of West Virginia were used in these analyses.
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