This Maple application computes the perimeter of a tract of land based on the latitude and longitude measurements marking its corners. The distance formula used comes from http://jan.ucc.nau.edu/~cvm/latlongdist.html This formula is not a Great Circle Distance Formula. However, the Great Circle Distance for points as close together as those in a tract of farm land will not differ appreciably from the straight line formula. There is probably more error due to the topography of the terrain.