// UnionPolygons tries to merge polygons.
// Returns a single (Multi)Polygon.
// Destroys polygons and returns new allocated (Multi)Polygon as necessary.
func (this *Geos) UnionPolygons(polygons []*Geom) *Geom {
if len(polygons) == 0 {
return nil
}
if len(polygons) == 1 {
return polygons[0]
}
multiPolygon := this.MultiPolygon(polygons)
if multiPolygon == nil {
return nil
}
defer this.Destroy(multiPolygon)
result := C.GEOSUnaryUnion_r(this.v, multiPolygon.v)
if result == nil {
return nil
}
return &Geom{result}
}
func cGEOSUnaryUnion(g *C.GEOSGeometry) *C.GEOSGeometry {
handlemu.Lock()
defer handlemu.Unlock()
return C.GEOSUnaryUnion_r(handle, g)
}