[Gdal-dev] [OT] determining EPSG codes

[Frank Warmerdam]

On 1/20/06, Thom DeCarlo <t.r.decarlo at larc.nasa.gov> wrote:
> Hi,
> I'm trying to figure out how to load shapefiles into a PostGIS database.
> (I'm also learning about PostGIS.) The next thing on my list of things to
> learn is how to determine the map projection EPSG code for my data files. I
> went to the EPSG.org website and downloaded lots of documentation and a
> pretty nice little Access database containing all the codes and their
> descriptions. However, I haven't found any simple way to determine, given a
> Projection+Datum+Ellipsoid, how to find the EPSG code.
>

Thom,

Are you wanting to do this programmatically or just
adhoc for a few layers?  For adhoc searches I
generally just grep around in the files like the PROJ.4
"epsg" file and compare definitions that seem reasonable.

To do it programmatically is pretty hard since there are
so many items to check.

To do it with WKT coordinate system descriptions, you
can sometimes just search for the EPSG authority code
on the PROJCS definition to get the EPSG code.   It isn't
always there though.

Best regards,

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