retrieve coordinates in matrix form
Value
matrix with coordinates (X, Y, possibly Z and/or M) in rows, possibly followed by integer indicators L1,...,L3 that point out to which structure the coordinate belongs; for POINT this is absent (each coordinate is a feature), for LINESTRING L1 refers to the feature, for MULTILINESTRING L1 refers to the part and L2 to the simple feature, for POLYGON L1 refers to the main ring or holes and L2 to the simple feature, for MULTIPOLYGON L1 refers to the main ring or holes, L2 to the ring id in the MULTIPOLYGON, and L3 to the simple feature.
For POLYGONS, L1 can be used to identify exterior rings and inner holes.
The exterior ring is when L1 is equal to 1. Interior rings are identified
when L1 is greater than 1. L2 can be used to differentiate between the
feature. Whereas for MULTIPOLYGON, L3 refers to the MULTIPOLYGON
feature and L2 refers to the component POLYGON.