Java Code Examples for com.vividsolutions.jts.geom.Envelope#expandBy()

public void zoom(Envelope zoomEnv) {
  if (zoomEnv == null)
    return;

  if (zoomEnv.isNull()) {
    viewport.zoomToInitialExtent();
    return;
  }
  double averageExtent = (zoomEnv.getWidth() + zoomEnv.getHeight()) / 2d;
  // fix to allow zooming to points
  if (averageExtent == 0.0)
    averageExtent = 1.0;
  double buffer = averageExtent * 0.1;
  zoomEnv.expandBy(buffer);
  viewport.zoom(zoomEnv);
}
 

private Envelope createTapEnvelope(Coordinate coord, double lat, double lng, float zoom) {
    Envelope envelope = new Envelope(coord);

    // Creating a reasonably sized envelope around the tap location.
    // Tweak the TAP_PIXEL_TOLERANCE to get a better sized box for your needs.
    double degreesLngPerPixel = degreesLngPerPixel(zoom);
    double deltaX = degreesLngPerPixel * TAP_PIXEL_TOLERANCE;
    double deltaY = scaledLatDeltaForMercator(deltaX, lat);
    envelope.expandBy(deltaX, deltaY);
    return envelope;
}
 

private void computeBoundingBox() {
	Envelope vertexEnv = computeVertexEnvelope(initialVertices);
	Envelope segEnv = computeVertexEnvelope(segVertices);

	Envelope allPointsEnv = new Envelope(vertexEnv);
	allPointsEnv.expandToInclude(segEnv);

	double deltaX = allPointsEnv.getWidth() * 0.2;
	double deltaY = allPointsEnv.getHeight() * 0.2;

	double delta = Math.max(deltaX, deltaY);

	computeAreaEnv = new Envelope(allPointsEnv);
	computeAreaEnv.expandBy(delta);
}
 

/**
 * Given a set of points stored in the kd-tree and a line segment defined by
 * two points in this set, finds a {@link Coordinate} in the circumcircle of
 * the line segment, if one exists. This is called the Gabriel point - if none
 * exists then the segment is said to have the Gabriel condition. Uses the
 * heuristic of finding the non-Gabriel point closest to the midpoint of the
 * segment.
 * 
 * @param p
 *          start of the line segment
 * @param q
 *          end of the line segment
 * @return a point which is non-Gabriel
 * or null if no point is non-Gabriel
 */
private Coordinate findNonGabrielPoint(Segment seg) {
	Coordinate p = seg.getStart();
	Coordinate q = seg.getEnd();
	// Find the mid point on the line and compute the radius of enclosing circle
	Coordinate midPt = new Coordinate((p.x + q.x) / 2.0, (p.y + q.y) / 2.0);
	double segRadius = p.distance(midPt);

	// compute envelope of circumcircle
	Envelope env = new Envelope(midPt);
	env.expandBy(segRadius);
	// Find all points in envelope
	List result = kdt.query(env);

	// For each point found, test if it falls strictly in the circle
	// find closest point
	Coordinate closestNonGabriel = null;
	double minDist = Double.MAX_VALUE;
	for (Iterator i = result.iterator(); i.hasNext();) {
		KdNode nextNode = (KdNode) i.next();
		Coordinate testPt = nextNode.getCoordinate();
		// ignore segment endpoints
		if (testPt.equals2D(p) || testPt.equals2D(q))
			continue;

		double testRadius = midPt.distance(testPt);
		if (testRadius < segRadius) {
			// double testDist = seg.distance(testPt);
			double testDist = testRadius;
			if (closestNonGabriel == null || testDist < minDist) {
				closestNonGabriel = testPt;
				minDist = testDist;
			}
		}
	}
	return closestNonGabriel;
}
 

public Envelope queryEnvelope() {
  Envelope queryEnv = new Envelope(p);
  queryEnv.expandBy(tolerance);
  return queryEnv;
}