The ST_CoveredBy method tests if the geometry-expression is completely covered by geo2.
geometry-expression.ST_CoveredBy( geo2 ) is equivalent to
geo2.ST_Covers( geometry-expression ).
This predicate is similar to ST_Within except for one subtle difference. The ST_Within predicate
requires that one or more interior points of the geometry-expression lie in the interior of geo2.
For ST_CoveredBy(), the method returns 1 if no point of the geometry-expression lies outside of
geo2, regardless of whether interior points of
the two geometries intersect.
ST_CoveredBy can be used with geometries in round-Earth spatial reference
If the geometry-expression contains circular strings, then these are interpolated to line strings.
The following example tests if a line is covered by a polygon. The line is
completely covered by the polygon so the example returns 1.
If ST_Within was used in place of ST_CoveredBy,
ST_Within would return 0.
The following example lists the ShapeIDs where the given point is
within the Shape geometry. This example returns the result 3,5,6.
Note that ShapeID 6 is listed even though the point intersects
that row's Shape polygon only at the polygon's boundary.
SELECT LIST( ShapeID ORDER BY ShapeID )
WHERE NEW ST_Point( 1, 4 ).ST_CoveredBy( Shape ) = 1