Simplifies a
Geometry using the Visvalingam-Whyatt area-based algorithm. Ensures that any polygonal geometries returned are valid. Simple lines are not guaranteed to remain simple after simplification. All geometry types are handled. Empty and point geometries are returned unchanged. Empty geometry components are deleted.
The simplification tolerance is specified as a distance. This is converted to an area tolerance by squaring it.
Note that in general this algorithm does not preserve topology - e.g. polygons can be split, collapse to lines or disappear holes can be created or disappear, and lines can cross.
Known Bugs
Not yet optimized for performance
Does not simplify the endpoint of rings
To Do
Allow specifying desired number of vertices in the output
distanceTolerance - distanceTolerance the tolerance to use
Returns:
a simplified version of the geometry
public void setDistanceTolerance(double distanceTolerance)
Sets the distance tolerance for the simplification. All vertices in the simplified geometry will be within this distance of the original geometry. The tolerance value must be non-negative.
Parameters:
distanceTolerance - distanceTolerance the approximation tolerance to use
public void setEnsureValid(boolean isEnsureValidTopology)
Controls whether simplified polygons will be "fixed" to have valid topology. The caller may choose to disable this because:
valid topology is not required
fixing topology is a relative expensive operation
in some pathological cases the topology fixing operation may either fail or run for too long