Roger, in Bangkok wrote: > Given a know wingspan, and the approximate height of the 4 balconies, > shouldn't be too difficult to approximate how close:-) I don't think so. There are is one more unknown value: the lens used. But maybe that value can be estimated from the curvature of lines that are known to be straight. -- Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: www.voti.nl/hvu -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist