PostGIS
Synopsis
boolean +`*`+ST_CoveredBy*(`geometry `geomA, geometry
geomB`)`;
boolean +`*`+ST_CoveredBy*(`geography `geogA, geography
geogB`)`;
Description
Returns true if no point in Geometry/Geography A lies outside
Geometry/Geography B. Equivalently, tests if every point of geometry A
is inside (i.e. intersects the interior or boundary of) geometry B.
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Performed by the GEOS module
Availability: 1.2.2
| this is the "allowable" version that returns a boolean, not an integer. |
Not an OGC standard, but Oracle has it too.
Examples
--a circle coveredby a circle
SELECT ST_CoveredBy(smallc,smallc) As smallinsmall,
ST_CoveredBy(smallc, bigc) As smallcoveredbybig,
ST_CoveredBy(ST_ExteriorRing(bigc), bigc) As exteriorcoveredbybig,
ST_Within(ST_ExteriorRing(bigc),bigc) As exeriorwithinbig
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,
ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;
--Result
smallinsmall | smallcoveredbybig | exteriorcoveredbybig | exeriorwithinbig
--------------+-------------------+----------------------+------------------
t | t | t | f
(1 row)