public IGeometry Union()
{
if (inputPolys.Count == 0)
return null;
geomFactory = Factory();
/**
* A spatial index to organize the collection
* into groups of close geometries.
* This makes unioning more efficient, since vertices are more likely
* to be eliminated on each round.
*/
var index = new STRtree(StrtreeNodeCapacity);
foreach (IGeometry item in inputPolys)
index.Insert(item.EnvelopeInternal, item);
var itemTree = index.ItemsTree();
var unionAll = UnionTree(itemTree);
return unionAll;
}
public void TestStrIndex()
{
STRtree ndx = new STRtree();
foreach (var v in CreateTestGeometries(1000, 0.0, 0.0, 3000.0, 3000.0))
ndx.Insert(v.EnvelopeInternal, v);
ndx.Build();
IEnvelope queryExtents = new Envelope(100.0, 120.0, 100.0, 120.0);
IList matches = ndx.Query(queryExtents);
foreach (IGeometry list in matches)
{
Assert.IsTrue(list.EnvelopeInternal.Intersects(queryExtents), "a result from the index does not intersect the query bounds");
}
}