ST_CompareWKT method

ST_SpatialRefSys::ST_CompareWKT(transform-definition-1,transform-definition-2)

Name	Type	Description
transform-definition-1	LONG VARCHAR	The first spatial reference system definition text
transform-definition-2	LONG VARCHAR	The second spatial reference system definition text

BIT Returns 1 if the two spatial reference systems are logically equivalent, otherwise 0.

Determines if two spatial reference systems (defined by WKT) are logically equivalent. The systems are considered logically equal if they are defined by the same authority with the same identifier or if the strings are exactly equal.

SQL/MM (ISO/IEC 13249-3: 2006) Vendor extension

The following example shows that two spatial reference systems are considered equal even though they have different names:

SELECT  ST_SpatialRefSys::ST_CompareWKT(
    'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]'
,   'GEOGCS["WGS 84 alternate name",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]'
) Considered_Equal

The following example shows two spatial reference systems that are considered non-equal because they are defined by different authorities:

SELECT  ST_SpatialRefSys::ST_CompareWKT(
    'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]'
,   'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["AnotherAuthority","4326"]]'
) Considered_NotEqual

ST_CompareWKT method

Syntax

Parameters

Returns

Remarks

Standards and compatibility

Example