On 23/12/10 16:13, George C wrote: > Has anyone ever heard of HRTI? HRTI is simple a very accurate DEM with very high spatial resolution. It's not a format for data storage or transportation, rather a (sub-)technology. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org Member of ACCU, http://accu.org