[mkgmap-dev] Program exit codes

Tue Jan 20 13:27:01 GMT 2009

First, let me introduce myself to the list.  I'm new to geosystems,
but learning quickly after I acquired a GPS receiver two weeks ago.

I've written a makefile to turn SRTM elevation data into vector contour
maps (I'll write it up on OpenStreetMap.org once I'm happy with it).
One of the problems[1] I've had is that mkgmap exits with return code 0
always, even on failure.  This means that the makefile blindly continues
to make its dependents, with a missing or invalid .img file - or in the
worst case, an old, out-of-date one.  If you were to add System.exit(1)
in appropriate places (probably just the exception handler in main()?) -
I'd be really grateful, and so probably would others.

[1] The biggest problem I had was with re-referencing the EGM96 data
    to OSGM02 - until I realised that the difference is well within
    the 1-metre precision of the source data, never mind its accuracy!

BTW, does mkgmap dislike negative ID values when reading OSM files?
gpsbabel writes these when writing, and I was wondering whether that's
what was causing empty tiles in my first attempt.