[OSRS-PROJ] Changes in EPSG codes?

Frank Warmerdam warmerdam at pobox.com
Fri Oct 24 06:26:39 PDT 2003


Jan-Oliver Wagner wrote:
> Hi,
> 
> I am troubled with the EPSG codes as in different versions of proj:
> 
> In Version 4.4.5 there is a code 31493 which is not there anymore
> in Version 4.4.7 (where a new code is used for the same projection:
> 31467).
> 
> First of all I wonder, whether this is a fix in proj or a change in
> EPSG?
> 
> The trouble I have is that a UMN MapServer WMS application running with
> proj 4.4.5 can not be accessed from a WMS Client that uses proj 4.4.7.
> 
> Is this a common problem? Is there a common solution?

Jan-Oliver,

This reflects a change in the EPSG database.  In theory I think it would
be possible to try and do something to merge in deleted codes from old
databases to retain better backward compatibility but I haven't tried to
do that.

I know this sort of thing can be quite annoying, and I don't know why
EPSG actually removes superceeded coordinate systems.  I had previously
thought this was not their policy.

The "changes" table in the EPSG db has a corresponding record that
reads:

2000.101,2000-03-07 00:00:00,2000-03-07 00:00:00,Jean-Patrick Girbig; IHS Energy,Amend Germany 
CS,HorizCS,31491-95,Changes name from DHDN / Germany zone x to DHDN / Gauss zone x.,Replaced Germany projCS 31491-95 
with 31461-65 respectively.  Deleted proj 18101-05.

What I would kind of like to have is a n "epsg_plus" table with all current
EPSG definitions, plus ones deleted from older versions, plus ESRI custom
codes.  This could then be used by folks wanting to maintain a maximimally
fleshed out set of definitions for MapServer and similar applications.
However, building such a thing is not a trivial effort.

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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