* radian arc distance of the point from the center point of the
* image, on the earth. This slope calculation does take the
* earth's curvature into account, based on the spherical model.
*/
protected double calculateLOSslope(LatLonPoint cord, float arc_dist) {
DTEDFrameCache frameCache = layer.frameCache;
if (frameCache == null) {
return 0;
}
int xyheight = frameCache.getElevation(cord.getLatitude(),
cord.getLongitude());
double ret = 0;
double P = Math.sin(arc_dist)
* (xyheight + Planet.wgs84_earthEquatorialRadiusMeters);