Re: [Geotools-gt2-users] How to get an SRID for srsName

[Jody G. <jga...@re...>]

There are a couple ways of talking about the same thing - use the CRS 
utility class to figure it out. SRID is kind of meaningless; or at least 
the meaning is defined by you for your application; I personally use 
SRID to mean "EPSG:<code>" and use the SRID number as my <code>. You 
will find that often the PostGIS spatial_ref_sys table is set up in this 
manner as well.

srsName is used when communicating with WFS and WMS; it is often a 
string for the form: "EPSG:4326", or it could be more complicated, the 
GeoTools library does a pretty good job of handling this for you using 
CRS.decode( ... ) method.

Farrukh Najmi wrote:
> Current code base allows lookup of a JTS GeometryFactory using an SRID using the following:
>
> http://javadoc.geotools.fr/2.5/org/geotools/factory/Hints.html#JTS_SRID
>
> Problem is I only have an srsName to start with.
>   
Don't worry about it too much; JTS does not care (or use) the SRID 
value; try and keep track of a CoordinateReferenceSystem object instead.
> Thus, I am looking for a way to get an SRID from a srsName.
>
> How can I do this using geotools? If geotools does not support this, how can I use the spatial_ref_sys in postgis to do the lookup. Thanks for any advice.
>   
You can query the table yourself and use CRS.fromWKT( ... ) - this is 
how the the PostGISDataStore returns your features with the correct 
CoordinateReferneceSystem.

Here are the docs for CRS:
- http://docs.codehaus.org/display/GEOTDOC/01+CRS+Helper+Class

Cheers,
Jody