We had the same problem with our local x/y projections. As far as I
have found out, the digitizing program needs to know the size of a base
unit in the projection used. For UTM these are meters, for state plane feet
and for latlon degrees. In an xy projection, the units are undefined 
(src/gislib/proj2.c). As most of our xy coordinate systems are measured
in meters, I changed the UNDEFINED in this file to METERS, but if someone
has a better solution I would like to hear of it.

Jan Hartmann
Faculty of Environmental Sciences
University of Amsterdam

