Dorrington, Albert wrote:
Initially our code was rather inefficient, considering that once the
list of polygons is defined, it does not change for the duration
of our search.
You might want to construct a geometry index that can be used to speed
up point-in-polygon tests. JTS has R-trees and Quadtrees.
protected double calculateCost(Point point) {
ret = costValue;
for (Polygon polygon : polygons ) {
if (point.intersects(polygon)) {
ret = 0;
break;
}
}
return ret;
}
The code would look something like:
protected double calculateCost(Point point) {
final Envelope searchEnvelope = new Envelope(point):
for (final Object o : spatialIndex.query(searchEnvelope)) {
final Polygon p = (Polygon)o;
if (point.intersects(p) {
return 0;
}
}
return costValue;
}
where spatialIndex is something like:
final SpatialIndex spatialIndex = new STRTree();
for (final Polygon p : polygons) {
spatialIndex.insert(p);
}
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