Class CascadedPolygonUnion

java.lang.Object
org.locationtech.jts.operation.union.CascadedPolygonUnion

public class CascadedPolygonUnion extends Object
Provides an efficient method of unioning a collection of Polygonal geometries. The geometries are indexed using a spatial index, and unioned recursively in index order. For geometries with a high degree of overlap, this has the effect of reducing the number of vertices early in the process, which increases speed and robustness.

This algorithm is faster and more robust than the simple iterated approach of repeatedly unioning each polygon to a result geometry.

Author:
Martin Davis
  • Constructor Details

  • Method Details

    • union

      public static Geometry union(Collection polys)
      Computes the union of a collection of Polygonal Geometrys.
      Parameters:
      polys - a collection of Polygonal Geometrys
    • union

      public static Geometry union(Collection polys, UnionStrategy unionFun)
      Computes the union of a collection of Polygonal Geometrys.
      Parameters:
      polys - a collection of Polygonal Geometrys
    • union

      public Geometry union()
      Computes the union of the input geometries.

      This method discards the input geometries as they are processed. In many input cases this reduces the memory retained as the operation proceeds. Optimal memory usage is achieved by disposing of the original input collection before calling this method.

      Returns:
      the union of the input geometries or null if no input geometries were provided
      Throws:
      IllegalStateException - if this method is called more than once