[postgis-users] srid for epsg 26915

[David Fawcett]

OK, that makes sense.

So, it works well when installing additional SRS' , you won't mess up
your stock spatial_ref_sys.

The use case that I was going after was where a co-worker wanted to
know what srid to use when importing data from a shapefile.  I was
attempting to use spatialreference.org as a reference to confirm what
the standard SRID for this SRS in PostGIS was.  I guess that this
conflict comes up for SRS' that are part of the stock install.

Maybe there is a need for another line on the spatialreference.org
page for 'PostGIS SRID' ?

Of course,  if one already has rights to add data to the db, you can
just run a simple (if you know the EPSG code):

SELECT *
  FROM public.spatial_ref_sys
WHERE auth_name = 'EPSG'
      AND auth_srid = 26915;

David.

On Wed, Sep 22, 2010 at 12:19 PM, David William Bitner
<bitner at gyttja.org> wrote:
> 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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