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Discussion: SDO_SRID use it or not?
Keyword tags:
coordinate
Spatial
SRID
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bolicja bolicja |
SDO_SRID use it or not?
Jan 4 2008, 6:42 AM EST Can someone explain to me what the (dis-) advantage is of setting the SDO_SRID to a specific spatial reference system compared to keep it at a NULL value. All the data that would be used have the same SDO_SRID value (90112) 0 out of 2 found this valuable. Do you? |
 l_paolini |
RE: SDO_SRID use it or not?
Jan 4 2008, 11:00 AM EST If you do not set the SRID for your data, Oracle Spatial will not be able to apply coordinate tranformation to a different SRID. In some functions this is a required information. I suggest that you take a look in the documentation page http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28400/sdo_cs_concepts.htm#i882173 to get additional information. 0 out of 3 found this valuable. Do you? |
 cewoodbu |
RE: SDO_SRID use it or not?
Jan 16 2008, 6:15 PM EST The SRID is mainly used when doing transformations with either coordinate systems or units. It tells Oracle how your data is stored. You do not need to use an SRID for most projected coordinate if you are just storing data and doing basic analysis on that data. Having an SRID is most important when your data uses Long/Lat or unprojected coordinates. Without the SRID, Oracle will treat the data as a rectagular coordinate system with a range of +-180 meters by +-90 meters. This will give you incorrect results in most if not all of the of the spatial analysis procedures like SDO_RELATE. If Oracle knows the data is geographic, it will take into account the earth's curvature and how it affects filter areas. 2 out of 3 found this valuable. Do you? |
