Hi, I am having some trouble in calibrating a bitmap image to be used as surface layer. I believe this is quite a basic problem but I havn't find anything in the archives. I need to insert data of 2 different points, so entrance of the cave is 0 0 and I can get the relevant bitmap pixels data from a software like Microsoft Paint. Now, the question is how should I get the data for the second point? I have no knowledge of where the stations are compared to the surface. Sorry but I'm really new to coordinates, GIS and all this stuff....and wonder how to proceed. And also, to make sure the scale is correct I should just export tha map with same scale as the surface map scanned, is this correct or I am missing something? thanks a lot for yr help Best Andrea Arriva Tiscali Mobile! Acquista la tua SIM Tiscali a soli €5 e scopri la semplicità e la convenienza del nuovo servizio per il tuo cellulare. Passa a Tiscali Mobile http://abbonati.tiscali.it/promo/tiscalimobile/