I'm looking for a reference that lists a standard SRID for a given CRS. Do RDMS's utilize a standardized SRID, such as OGC? Or is it unique to the RDMS?
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2It's worse than that. Every application has different rules. In Esri terms, the coordinate system is just a small piece of the spatial reference, and there could be hundreds or thousands of SRIDs that refer to the same coordinate system, which might not be in any OGC list.– VinceCommented Mar 24, 2016 at 13:45
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That is very unfortunate. Do you know if the OGC has intentions of pushing for a standard SRID?– JylerCommented Mar 24, 2016 at 14:10
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Coordinate system descriptions can be standardized. Coordinate systems can be standardized to a point (though that was done long before OGC took notice), but It's not the place of standards bodies to interfere with implementation details (for which defining "spatial reference" would qualify).– VinceCommented Mar 24, 2016 at 14:43
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1 Answer
Although there is a lot of variety in proprietary naming as @Vince says in the comments, there is considerable standardization provided by the European Petroleum Survey Group (aka EPSG). Most GIS systems reference/understand the EPSG SRID codes for some years now and thereby attain a considerable degree of uniformity between systems. OGC is compliant with EPSG as are QGIS (which is built on OGC), GRASS, SAGA, ArcGIS and most other systems I have seen.
PostGIS, SpatialLite and MySQL all conform to EPSG SRID codes and as far as I know so do Oracle Spatial and SQL-server. Even spatially enabled NoSQL databases such as Mongo and REDIS both comply with EPSG. Also any system using the Proj4 projection libraries (including some web mapping utilities etc) will be compliant to the EPSG codes. So, although it can look like a nightmare at first glance, considerable conformity/interoperability is actually achieved across the majority of the vast array of GIS software.
To avoid issues with any proprietary naming of SRIDs, I recommend sticking to EPSG SRID codes wherever possible. A good source of information on these codes with some cross-referencing in places to other well-known proprietary codes (e.g. ESRI) see Spatial Org.
answered Mar 24, 2016 at 16:06
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So if I am creating a spatial table directly in a SQL Server database, does it follow that I can set SRID = the EPSG code for the spatial reference I am assigning?– JylerCommented Mar 24, 2016 at 16:15
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1I'm more of a PostGIS guy, but according to the SQL Server documentation: "The spatial reference identification system is defined by the European Petroleum Survey Group (EPSG) standard, which is a set of standards developed for cartography, surveying, and geodetic data storage. This standard is owned by the Oil and Gas Producers (OGP) Surveying and Positioning Committee." So - I take that to mean (like PosGIS) the answer is 'yes' (and if you don't define it - it looks like the default is EPSG 4326 - aka WGS84) Commented Mar 24, 2016 at 16:18