When I run the alsk projection in inverse mode and enter the projection origin (0,0) I get the wrong answer. If I move over by one unit, the answer is correct. Anybody else seen this? >proj +proj=alsk -I 0 0 56dE 64dN 1 1 151d59'59.926"W 64d0'0.032"N -1 -1 152d0'0.074"W 63d59'59.968"N Thanks :-) fyw