At 14:32 19.8.1997 -0400, you wrote: >With your great help I have got the sites file out of DEM. the format of data in >the file looks like > 724675|4385245#259 > 724725|4385245#259 > >But when I ran s.surf.tps, it says "ERROR: zero points in the given region!" The Houxiang, The correct format is: 724675|4385245|#259 Regards, Jaro Hofierka