Gavin<br><br>This is good to know. If you say "south-facing projections", is this large-scale data?<br>I have loads of small scale data and are yet to bump into projection problems, but I know its comming.<br><br>
<br>Thanks for the info...<br><br>Regards<br>Sarel <br><br><div class="gmail_quote">On Tue, Feb 17, 2009 at 3:14 PM, Gavin Fleming <span dir="ltr"><<a href="mailto:GavinF@mintek.co.za">GavinF@mintek.co.za</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">In PostGIS: SELECT * FROM spatial_ref_sys;<br>
<br>
The only problem is, for SA projections like the LOs on Hartebeesthoek<br>
datum, proj4 can't handle a south-facing projection (yet) and be aware<br>
in PostGIS that while their EPSG codes are defined properly, the<br>
matching proj4 strings are undefined (at 1.2 at any rate).<br>
<br>
I have some LO 27 data in PostGIS that QGIS and uDIG couldn't project,<br>
yet GeoServer did. For the South African EPSG LO definitions to apply<br>
though, you have to swap your x and y signs (though not the axes).<br>
<br>
A workaround in South Africa is to use normal Transverse Mercator on<br>
Hartebeesthoek and standardise the axes and signs (i.e. make them look<br>
conventional like the rest of the world) - then just define your own<br>
EPSG (and proj4) code and add a record to PostGIS.<br>
<br>
Here's an Albers one I use a lot:<br>
<br>
srid,auth_name,auth_srid,srtext,proj4text<br>
40000,EPSG,40000,PROJCS["South Africa Albers Equal Area<br>
24",GEOGCS["GCS_Hartebeesthoek_1994",DATUM["D_Hartebeesthoek_1994",SPHER<br>
OID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["D<br>
egree",0.0174532925199433]],PROJECTION["Albers"],PARAMETER["False_Eastin<br>
g",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",24.<br>
0],PARAMETER["Standard_Parallel_1",-18.0],PARAMETER["Standard_Parallel_2<br>
",-32.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]],+proj=ae<br>
a +lat_1=-18 +lat_2=-32 +lat_0=0 +lon_0=24 +x_0=0 +y_0=0 +ellps=WGS84<br>
+units=m +no_defs<br>
<br>
Gavin<br>
<div><div></div><div class="Wj3C7c"><br>
<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a><br>
[mailto:<a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a>] On Behalf Of Tim Sutton<br>
Sent: 17 February 2009 13:57 PM<br>
To: Africa local chapter discussions<br>
Subject: Re: [OSGeo Africa] SRID<br>
<br>
Hi<br>
<br>
<br>
On Tue, Feb 17, 2009 at 12:10 PM, <<a href="mailto:bartvde@osgis.nl">bartvde@osgis.nl</a>> wrote:<br>
> Hi,<br>
><br>
> SRID is an Oracle term so I assume you are talking about Oracle<br>
Spatial.<br>
><br>
> It's in a table called CS_SRS in the MDSYS schema:<br>
><br>
> select * from MDSYS.CS_SRS<br>
><br>
> Best regards,<br>
> Bart<br>
><br>
>> Hi All,<br>
>><br>
>> First posting!!!<br>
>><br>
>> Where can I get a list of SRID's.<br>
>><br>
>> Regards,<br>
>><br>
>> Clinton Papenfus<br>
>> 0833767083<br>
<br>
<br>
<br>
For a user friendly list of CRS's you can also click on the icon in<br>
the bottom right corner of the QGIS window, and you will be presented<br>
with a CRS list. Click on any CRS entry to see its proj4 definition.<br>
<br>
Regards<br>
<br>
Tim<br>
<br>
--<br>
Tim Sutton - QGIS Project Steering Committee Member (Release Manager)<br>
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