/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.geo;
import java.text.ParseException;
import java.util.Arrays;
/**
* Represents a closed polygon on the earth's surface. You can either construct the Polygon directly yourself with {@code double[]}
* coordinates, or use {@link Polygon#fromGeoJSON} if you have a polygon already encoded as a
* <a href="http://geojson.org/geojson-spec.html">GeoJSON</a> string.
* <p>
* NOTES:
* <ol>
* <li>Coordinates must be in clockwise order, except for holes. Holes must be in counter-clockwise order.
* <li>The polygon must be closed: the first and last coordinates need to have the same values.
* <li>The polygon must not be self-crossing, otherwise may result in unexpected behavior.
* <li>All latitude/longitude values must be in decimal degrees.
* <li>Polygons cannot cross the 180th meridian. Instead, use two polygons: one on each side.
* <li>For more advanced GeoSpatial indexing and query operations see the {@code spatial-extras} module
* </ol>
* @lucene.experimental
*/
public final class Polygon {
private final double[] polyLats;
private final double[] polyLons;
private final Polygon[] holes;
/** minimum latitude of this polygon's bounding box area */
public final double minLat;
/** maximum latitude of this polygon's bounding box area */
public final double maxLat;
/** minimum longitude of this polygon's bounding box area */
public final double minLon;
/** maximum longitude of this polygon's bounding box area */
public final double maxLon;
/**
* Creates a new Polygon from the supplied latitude/longitude array, and optionally any holes.
*/
public Polygon(double[] polyLats, double[] polyLons, Polygon... holes) {
if (polyLats == null) {
throw new IllegalArgumentException("polyLats must not be null");
}
if (polyLons == null) {
throw new IllegalArgumentException("polyLons must not be null");
}
if (holes == null) {
throw new IllegalArgumentException("holes must not be null");
}
if (polyLats.length != polyLons.length) {
throw new IllegalArgumentException("polyLats and polyLons must be equal length");
}
if (polyLats.length != polyLons.length) {
throw new IllegalArgumentException("polyLats and polyLons must be equal length");
}
if (polyLats.length < 4) {
throw new IllegalArgumentException("at least 4 polygon points required");
}
if (polyLats[0] != polyLats[polyLats.length-1]) {
throw new IllegalArgumentException("first and last points of the polygon must be the same (it must close itself): polyLats[0]=" + polyLats[0] + " polyLats[" + (polyLats.length-1) + "]=" + polyLats[polyLats.length-1]);
}
if (polyLons[0] != polyLons[polyLons.length-1]) {
throw new IllegalArgumentException("first and last points of the polygon must be the same (it must close itself): polyLons[0]=" + polyLons[0] + " polyLons[" + (polyLons.length-1) + "]=" + polyLons[polyLons.length-1]);
}
for (int i = 0; i < polyLats.length; i++) {
GeoUtils.checkLatitude(polyLats[i]);
GeoUtils.checkLongitude(polyLons[i]);
}
for (int i = 0; i < holes.length; i++) {
Polygon inner = holes[i];
if (inner.holes.length > 0) {
throw new IllegalArgumentException("holes may not contain holes: polygons may not nest.");
}
}
this.polyLats = polyLats.clone();
this.polyLons = polyLons.clone();
this.holes = holes.clone();
// compute bounding box
double minLat = Double.POSITIVE_INFINITY;
double maxLat = Double.NEGATIVE_INFINITY;
double minLon = Double.POSITIVE_INFINITY;
double maxLon = Double.NEGATIVE_INFINITY;
for (int i = 0;i < polyLats.length; i++) {
minLat = Math.min(polyLats[i], minLat);
maxLat = Math.max(polyLats[i], maxLat);
minLon = Math.min(polyLons[i], minLon);
maxLon = Math.max(polyLons[i], maxLon);
}
this.minLat = minLat;
this.maxLat = maxLat;
this.minLon = minLon;
this.maxLon = maxLon;
}
/** Returns a copy of the internal latitude array */
public double[] getPolyLats() {
return polyLats.clone();
}
/** Returns a copy of the internal longitude array */
public double[] getPolyLons() {
return polyLons.clone();
}
/** Returns a copy of the internal holes array */
public Polygon[] getHoles() {
return holes.clone();
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + Arrays.hashCode(holes);
result = prime * result + Arrays.hashCode(polyLats);
result = prime * result + Arrays.hashCode(polyLons);
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Polygon other = (Polygon) obj;
if (!Arrays.equals(holes, other.holes)) return false;
if (!Arrays.equals(polyLats, other.polyLats)) return false;
if (!Arrays.equals(polyLons, other.polyLons)) return false;
return true;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < polyLats.length; i++) {
sb.append("[")
.append(polyLats[i])
.append(", ")
.append(polyLons[i])
.append("] ");
}
if (holes.length > 0) {
sb.append(", holes=");
sb.append(Arrays.toString(holes));
}
return sb.toString();
}
/** Parses a standard GeoJSON polygon string. The type of the incoming GeoJSON object must be a Polygon or MultiPolygon, optionally
* embedded under a "type: Feature". A Polygon will return as a length 1 array, while a MultiPolygon will be 1 or more in length.
*
* <p>See <a href="http://geojson.org/geojson-spec.html">the GeoJSON specification</a>. */
public static Polygon[] fromGeoJSON(String geojson) throws ParseException {
return new SimpleGeoJSONPolygonParser(geojson).parse();
}
}