[gdal-dev] Re: srs definition for wgs84

[Peter J Halls]

Jukka,

    I do not have Geoserver, however, if it will support use of the 
SDO_CS.MAP_EPSG_SRID_TO_ORACLE and SDO_CS.MAP_ORACLE_SRID_TO_EPSG methods, then 
it should not matter what Oracle is doing internally.  I use these on those 
occasions where I receive data with the EPSG definition or am exporting to EPSG.

    By the way, the details are in Chapter 6 of the Oracle Spatial Developer's 
Guide, code B28400, which is freely available for download from the Oracle 11g 
documentation web pages.

Best wishes,

Peter

Rahkonen Jukka wrote:
> Hi,
> 
> I believe that Imran is willing to use Oracle data, once they are in, through Geoserver. On the other hand, I do not believe that Geoserver supports those Oracle SRIDs but it wants to see SRID=4326 for WGS84 data in Oracle. Therefore even the Oracle codes may be better in some way in this case they could be unusable. I have not tried ever with SRID=4326 in Oracle, but using SRID=2393 in Oracle works fine together with our EPSG:2393 data and Geoserver.
> 
> -Jukka-
> 
> 
> -----Alkuperäinen viesti-----
> Lähettäjä: Peter J Halls [mailto:P.Halls at york.ac.uk]
> Lähetetty: to 13.5.2010 16:02
> Vastaanottaja: Rahkonen Jukka
> Kopio: gdal-dev at lists.osgeo.org
> Aihe: Re: [gdal-dev] Re: srs definition for wgs84
>  
> Jukka,
> 
> Jukka Rahkonen wrote:
>> Peter J Halls <P.Halls <at> york.ac.uk> writes:
>>
>>> Imran,
>>>
>>>     the Oracle SRID value of 8192 *is* WGS84.  Oracle does not store the EPSG 
>>> values, but has its own set.  
>> Starting from Oracle 10g or something it supports also EPSG codes. Old codes are
>> still supported by Oracle but other programs usually do not understand Oracle
>> SRID codes. Fortunately they are no more needed. But I think that the correct
> 
>     from the (11g) Oracle Spatial reference manual:
> 
> "The Oracle Spatial coordinate system support is based on, but is not always 
> identical to, the European Petroleum Survey Group (EPSG) data model and dataset."
> 
> Methods are provided to express the Oracle SRID as EPSG WKT and to translate 
> between Oracle SRID values and EPSG values.  These are needed for programs which 
> do not understand the Oracle SRID values.
> 
> This means that, without care, Oracle reports will specify the Oracle SRID 
> values, which are those stored and used internally, rather than the EPSG values. 
>   Oracle also supports projections additional to the EPSG schema.  This seems to 
> be what Imran saw.
> 
> Yes, this change was introduced at 10g and replaced something rather different 
> (and which I have never used), but the current system does not simply use EPSG 
> as you imply.
> 
>> way to give target SRID with ogr Oracle driver is not to use -a_srs but the
>> Layer Creation Option -lco SRID=4326.
> 
> Agreed, although up to and including GDAL 1.6.n I have failed to get this method 
> to work when using the API.  The problem is more than likely something I've done 
> wrong and I have not yet tried 1.7.n.
> 
> Best wishes,
> 
> Peter
> 
>> -Jukka Rahkonen-
>>
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>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> 

-- 
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Peter J Halls, GIS Advisor, University of York
Telephone: 01904 433806     Fax: 01904 433740
Snail mail: Computing Service, University of York, Heslington, York YO10 5DD
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