[postgis-users] srid for epsg 26915

[David William Bitner]

David,

spatialreference.org uses a local SRID with a prepended '9' while
maintaining an auth_srid to match EPSG so as not to step on the toes of the
SRIDs that are already in the spatial_ref_sys table. While a bit ugly, this
is the intended behavior. It uses the '9' because there are no EPSG codes
that begin with a 9 so it is a clear namespace to not overwrite an EPSG code
regardless of what local SRID identifier is given at spatialreference.org.

Clear as mud?

David

On Wed, Sep 22, 2010 at 11:41 AM, David Fawcett <david.fawcett at gmail.com>wrote:

> A minor issue here, but I am looking for some clarification.
>
> I am seeking the correct PostGIS srid for UTM Z15N NAD83.
>
> If I query spatialreference.org,
> (http://spatialreference.org/ref/epsg/26915/postgis/)  I get:
>
> INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text,
> srtext) values ( 926915, 'epsg', 26915, '+proj=utm +zone=15
> +ellps=GRS80 +datum=NAD83 +units=m +no_defs ', 'PROJCS["NAD83 / UTM
> zone 15N",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS
>
> 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-93],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],AUTHORITY["EPSG","26915"],AXIS["Easting",EAST],AXIS["Northing",NORTH]]');
>
>
> From a fairly recent of PostGIS,
>
> SELECT srid, auth_name, auth_srid
> FROM public.spatial_ref_sys
> WHERE auth_srid = 26915
>
>
> I get:  26915 | EPSG | 26915
>
>
> I am assuming that the definition at spatial ref.org is wrong?
>
> David.
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>



-- 
************************************
David William Bitner
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