4.3 Spatial schema (ISO 19107)
147
Fig. 4.24. Operation representativePoint
boundary
Applied to an object the operation "boundary" returns the object's boundary that
is one dimension lower than the dimension of the object itself. In the case of a surface the boundary operator returns the curves around the surface. The object may
have a further internal structure.
larger object
boundary
Fig. 4.25. Operation boundary
closure
The operation "closure" combines an object with its boundary. Applied to a
GM _LineString the operation "closure" returns the GM _ LineString and its start and
end point.