[postgis-users] Question on datum names

[Frank Warmerdam]

Peter,

I agree that it is somewhat perverse to use the .prj extension if you
aren't going to match ArcGIS PE strings.  Either call it something
else (like .pgwkt for instance) or transform it.  The GDAL/OGR
packages' OGRSpatialReference class includes a morphToESRI() method
that will convert OGC/PostGIS/OGR Well Known Text to ESRI PE String
format reasonably well.

On Tue, May 29, 2012 at 2:45 PM, Peter N. Schweitzer
<pschweitzer at usgs.gov> wrote:
> On the web site from which I distribute spatial data, I provide shapefiles
> with projection information as a .prj file.  I've drawn the contents of
> these prj files from the srtext field of the spatial_ref_sys table.
>
> A user has pointed out to me that this is inconvenient for people running
> ArcGIS because ArcGIS expects to see different values as the name of the
> coordinate system and the datum.  I have not seen a standard that specifies
> these names.  Is there one?

Well, the defacto standard is whatever ArcGIS does.  They do publish
various information on this but it isn't a "standard" in the normal sense of
that world.  Note that OGC's Well Known Text format was an adaption of
ESRI PE Strings - hence the similar but not the same nature.

Best regards,
Frank

> It looks like I could change my .prj files to fit ArcGIS without much trouble.
> But would this change break other applications?  Are there GIS applications
> other than ArcGIS that rely strongly on these names?  How do others support
> portability of projection information in downloadable data using the shapefile
> format?
>
> Peter
> --
> Peter N. Schweitzer (MS 954, U.S. Geological Survey, Reston, VA 20192)
> (703) 648-6533  FAX: (703) 648-6252  email: pschweitzer at usgs.gov
> <http://geology.usgs.gov/peter/>
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