[postgis-users] adding customized projection definitions to spatial_ref_sys_table

[Frank Warmerdam]

On 10/28/05, christian.michels at eifelgeist.com
<christian.michels at eifelgeist.com> wrote:
> Hi matt,
>
>  thanx a lot for the link .... that helps very much constucting the proj4text input, BUT there is still one thing
>  I do not understand:
>
>  Taking one example from the spatial_ref_sys_table:
>
>  PROJCS["Anguilla 1957 / British West Indies Grid",GEOGCS["Anguilla 1957",DATUM["Anguilla_1957",SPHEROID["Clarke 1880 (RGS)",6378249.145,293.465,AUTHORITY["EPSG","7012"]],AUTHORITY["EPSG","6600"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4600"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-62],PARAMETER["scale_factor",0.9995],PARAMETER["false_easting",400000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AUTHORITY["EPSG","2000"]]
>
>  How do I get the AUTHORITY["EPSG","7012"]] for a customized prj system ?
>  What would be for example the AUTHORITY code for GEOGCS["GCS_WGS_1984"] and how do is exacly use the AUTHORITY withing the  PROJCS[...] string ??

Chris,

You could use AUTHORITY["ChrisMichels","1"] if you wanted, but
since this is a custom coordinate system, I would discourage your
using any authority entry for it at all.  The authority values are just
there so that folks can relate the coordinate system object to "well
known" dictionaries.  Mostly this means EPSG for now.  Since your
coordinate system is custom, it might as well have no authority code.

Best regards,
--
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