package com.vividsolutions.jts.operation.overlay.validate;
import java.util.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.algorithm.*;
/**
* Finds the most likely {@link Location} of a point relative to
* the polygonal components of a geometry, using a tolerance value.
* If a point is not clearly in the Interior or Exterior,
* it is considered to be on the Boundary.
* In other words, if the point is within the tolerance of the Boundary,
* it is considered to be on the Boundary; otherwise,
* whether it is Interior or Exterior is determined directly.
*
* @author Martin Davis
* @version 1.7
*/
public class FuzzyPointLocator
{
private Geometry g;
private double boundaryDistanceTolerance;
private MultiLineString linework;
private PointLocator ptLocator = new PointLocator();
private LineSegment seg = new LineSegment();
public FuzzyPointLocator(Geometry g, double boundaryDistanceTolerance)
{
this.g = g;
this.boundaryDistanceTolerance = boundaryDistanceTolerance;
linework = extractLinework(g);
}
public int getLocation(Coordinate pt)
{
if (isWithinToleranceOfBoundary(pt))
return Location.BOUNDARY;
/*
double dist = linework.distance(point);
// if point is close to boundary, it is considered to be on the boundary
if (dist < tolerance)
return Location.BOUNDARY;
*/
// now we know point must be clearly inside or outside geometry, so return actual location value
return ptLocator.locate(pt, g);
}
/**
* Extracts linework for polygonal components.
*
* @param g the geometry from which to extract
* @return a lineal geometry containing the extracted linework
*/
private MultiLineString extractLinework(Geometry g)
{
PolygonalLineworkExtracter extracter = new PolygonalLineworkExtracter();
g.apply(extracter);
List linework = extracter.getLinework();
LineString[] lines = GeometryFactory.toLineStringArray(linework);
return g.getFactory().createMultiLineString(lines);
}
private boolean isWithinToleranceOfBoundary(Coordinate pt)
{
for (int i = 0; i < linework.getNumGeometries(); i++) {
LineString line = (LineString) linework.getGeometryN(i);
CoordinateSequence seq = line.getCoordinateSequence();
for (int j = 0; j < seq.size() - 1; j++) {
seq.getCoordinate(j, seg.p0);
seq.getCoordinate(j + 1, seg.p1);
double dist = seg.distance(pt);
if (dist <= boundaryDistanceTolerance)
return true;
}
}
return false;
}
}
/**
* Extracts the LineStrings in the boundaries
* of all the polygonal elements in the target {@link Geometry}.
*
* @author Martin Davis
*/
class PolygonalLineworkExtracter
implements GeometryFilter
{
private List linework;
public PolygonalLineworkExtracter()
{
linework = new ArrayList();
}
/**
* Filters out all linework for polygonal elements
*/
public void filter(Geometry g)
{
if (g instanceof Polygon) {
Polygon poly = (Polygon) g;
linework.add(poly.getExteriorRing());
for (int i = 0; i < poly.getNumInteriorRing(); i++) {
linework.add(poly.getInteriorRingN(i));
}
}
}
/**
* Gets the list of polygonal linework.
*
* @return a List of LineStrings
*/
public List getLinework() { return linework; }
}