OGC Definition

There is none.

Oracle Spatial Definition

[OSUGR] defines CoveredBy as follows. "The opposite of COVERS. A.COVEREDBY B implies B COVERS A."

The FDO Oracle Provider implements this definition:

CoveredBy = coveredby as used in the third argument to the sdo_relate spatial operator, for example,
sdo_relate(a.GEOMETRY, MDSYS.SDO_GEOMETRY(2002, NULL, NULL, MDSYS.SDO_ELEM_INFO_ARRAY(1,2,1), MDSYS.SDO_ORDINATE_ARRAY(4,1, 8,1)), 'mask=coveredby').

PHP Code Implementation

The equivalent of the CoveredBy predicate can be expressed using MgGeometry methods as follows.

<?php
function CoveredBy ($geom1, $geom2) {
   $withinBool = $geom1->Within($geom2);
   if (!$withinBool) return $withinBool;
   $boundary1 = $geom1->Boundary();
   $boundary2 = $geom2->Boundary();
   $intersectBool = $boundary1->Intersects($boundary2);
   return $intersectBool;
}
?>

A Point and MultiPoint cannot be covered because they do not have boundaries.

Illustration

An endpoint of d and an endpoint of e intersect.