[MetaCRS] Axis order in CS Test file

Martin Davis mbdavis at refractions.net
Mon Nov 30 17:37:46 EST 2009


I'd really like to get this issue settled, since I'm currently cutting 
code to parse and execute the CS Test file format.  8^)

As I see it a summary of the arguments is:

Option #1 - axis order follows order specified by CS authority
- follows EPSG & OGC convention, which is currently the authority with 
most weight
- simpler for libraries which currently handle axis order explicitly

Option #2 - axis order of geodetic coordinates is always long/lat
- adheres to Principle of Least Surprise (order is consistent between 
src and tgt coordinates)
- simple to document as part of the CS Test format specification
- test format can be interpreted without reference to CS specification
- simpler for libs such as Proj4 and CS-Map which currently work this way

One other thing that to me seems to be in favour of Option #2 is that 
libs which currently handle axis order explicitly should be able to deal 
with this easily (as evidenced by Martin's reply).  Whereas this is not 
so much the case for Option #1 and libs which expect long/lat order.

Shall we put this to a vote?

-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022




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