[OSRS-PROJ] Proj.4 vs Geotrans

Frank Warmerdam warmerdam at pobox.com
Sun Mar 30 11:06:15 EST 2003


I would agree with the all the non-code style related statements so far
about the differences between Geotrans and PROJ.4.  I would like to add a
couple of additional points in favour of PROJ.4

   1) PROJ.4 has a well defined syntax for describing projections and
      coordinate systems for the end user, while Geotrans just has the API
      arguments. (I have a similar issue with GCTP)

   2) PROJ.4 has an active accessable public user community for help and

On the whole issue of source code style, and commenting.  I extracted the
3/7 parameter datum shifting support in PROJ.4 from Geotrans and I found the
Geotrans code very understandable to a layman such as myself.  I have never
felt comfortable pointing folks to the PROJ.4 code as a reference due to it's
relative inscrutibility.

In fact, I feel the good (if somewhat verbose) style of Geotrans speaks well
of the hard lessons learned by the military about development of software
systems.  Some of the pendantic rules they apply to development projects
these days are worthwhile.

I am also embarrassed to admit I don't own *any* texts, journals, or papers
on projections, or geodesy.  This is partly pathetic on my part, but should
also highlight that lots of people who may end up needing to understand the
code base may be ill equiped by background or references to deal with it
properly.  It isn't necessarily Gerald's problem to document everything for
me but this sort of situation will arise.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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