[turf] add bbox for arbitrary geometries (#769)

Author: ivovandongen

services-turf/src/main/java/com/mapbox/turf/TurfMeasurement.java

@@ -3,13 +3,16 @@
 import android.support.annotation.FloatRange;
 import android.support.annotation.NonNull;
 
+import com.mapbox.geojson.Geometry;
+import com.mapbox.geojson.GeometryCollection;
 import com.mapbox.geojson.LineString;
 import com.mapbox.geojson.MultiLineString;
 import com.mapbox.geojson.MultiPoint;
 import com.mapbox.geojson.Point;
 import com.mapbox.geojson.Polygon;
 import com.mapbox.geojson.MultiPolygon;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -333,6 +336,42 @@ public static double[] bbox(MultiPolygon multiPolygon) {
     return bboxCalculator(resultCoords);
   }
 
+  /**
+   * Takes an arbitrary {@link Geometry} and calculates a bounding box.
+   *
+   * @param geometry a {@link Geometry} object
+   * @return a double array defining the bounding box in this order {@code [minX, minY, maxX, maxY]}
+   * @since 2.0.0
+   */
+  public static double[] bbox(Geometry geometry) {
+    if (geometry instanceof Point) {
+      return bbox((Point) geometry);
+    } else if (geometry instanceof MultiPoint) {
+      return bbox((MultiPoint) geometry);
+    } else if (geometry instanceof LineString) {
+      return bbox((LineString) geometry);
+    } else if (geometry instanceof MultiLineString) {
+      return bbox((MultiLineString) geometry);
+    } else if (geometry instanceof Polygon) {
+      return bbox((Polygon) geometry);
+    } else if (geometry instanceof MultiPolygon) {
+      return bbox((MultiPolygon) geometry);
+    } else if (geometry instanceof GeometryCollection) {
+      List<Point> points = new ArrayList<>();
+      for (Geometry geo : ((GeometryCollection) geometry).geometries()) {
+        // recursive
+        double[] bbox = bbox(geo);
+        points.add(Point.fromLngLat(bbox[0], bbox[1]));
+        points.add(Point.fromLngLat(bbox[2], bbox[1]));
+        points.add(Point.fromLngLat(bbox[2], bbox[3]));
+        points.add(Point.fromLngLat(bbox[0], bbox[3]));
+      }
+      return TurfMeasurement.bbox(MultiPoint.fromLngLats(points));
+    } else {
+      throw new RuntimeException(("Unknown geometry class: " + geometry.getClass()));
+    }
+  }
+
   private static double[] bboxCalculator(List<Point> resultCoords) {
     double[] bbox = new double[4];
 

services-turf/src/test/java/com/mapbox/turf/TurfMeasurementTest.java

@@ -1,18 +1,16 @@
 package com.mapbox.turf;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-
-import com.mapbox.geojson.Feature;
-import com.mapbox.geojson.MultiLineString;
 import com.mapbox.core.TestUtils;
+import com.mapbox.geojson.Feature;
 import com.mapbox.geojson.FeatureCollection;
-import com.mapbox.geojson.Polygon;
+import com.mapbox.geojson.Geometry;
+import com.mapbox.geojson.GeometryCollection;
 import com.mapbox.geojson.LineString;
+import com.mapbox.geojson.MultiLineString;
+import com.mapbox.geojson.MultiPoint;
 import com.mapbox.geojson.MultiPolygon;
 import com.mapbox.geojson.Point;
+import com.mapbox.geojson.Polygon;
 
 import org.junit.Assert;
 import org.junit.Rule;
@@ -23,13 +21,19 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+
 public class TurfMeasurementTest extends TestUtils {
 
   private static final String LINE_DISTANCE_ROUTE_ONE = "turf-line-distance/route1.geojson";
   private static final String LINE_DISTANCE_ROUTE_TWO = "turf-line-distance/route2.geojson";
   private static final String LINE_DISTANCE_POLYGON = "turf-line-distance/polygon.geojson";
   private static final String TURF_ALONG_DC_LINE = "turf-along/dc-line.geojson";
   private static final String TURF_BBOX_POINT = "turf-bbox/point.geojson";
+  private static final String TURF_BBOX_MULTI_POINT = "turf-bbox/multipoint.geojson";
   private static final String TURF_BBOX_LINESTRING = "turf-bbox/linestring.geojson";
   private static final String TURF_BBOX_POLYGON = "turf-bbox/polygon.geojson";
   private static final String TURF_BBOX_MULTILINESTRING = "turf-bbox/multilinestring.geojson";
@@ -301,4 +305,40 @@ public void bboxFromMultiPolygon() throws IOException, TurfException {
     assertEquals(103, bbox[2], DELTA);
     assertEquals(3, bbox[3], DELTA);
   }
+
+  @Test
+  public void bboxFromGeometry() throws IOException, TurfException {
+    Geometry geometry = MultiPolygon.fromJson(loadJsonFixture(TURF_BBOX_MULTIPOLYGON));
+    double[] bbox = TurfMeasurement.bbox(geometry);
+
+    assertEquals(4, bbox.length);
+    assertEquals(100, bbox[0], DELTA);
+    assertEquals(0, bbox[1], DELTA);
+    assertEquals(103, bbox[2], DELTA);
+    assertEquals(3, bbox[3], DELTA);
+  }
+
+  @Test
+  public void bboxFromGeometryCollection() throws IOException, TurfException {
+    // Check that geometry collection and direct bbox are equal
+    MultiPolygon multiPolygon = MultiPolygon.fromJson(loadJsonFixture(TURF_BBOX_MULTIPOLYGON));
+    assertArrayEquals(TurfMeasurement.bbox(multiPolygon), TurfMeasurement.bbox(GeometryCollection.fromGeometry(multiPolygon)), DELTA);
+
+    // Check all geometry types
+    List<Geometry> geometries = new ArrayList<>();
+    geometries.add(Feature.fromJson(loadJsonFixture(TURF_BBOX_POINT)).geometry());
+    geometries.add(MultiPoint.fromJson(loadJsonFixture(TURF_BBOX_MULTI_POINT)));
+    geometries.add(LineString.fromJson(loadJsonFixture(TURF_BBOX_LINESTRING)));
+    geometries.add(MultiLineString.fromJson(loadJsonFixture(TURF_BBOX_MULTILINESTRING)));
+    geometries.add(Feature.fromJson(loadJsonFixture(TURF_BBOX_POLYGON)).geometry());
+    geometries.add(MultiPolygon.fromJson(loadJsonFixture(TURF_BBOX_MULTIPOLYGON)));
+    geometries.add(GeometryCollection.fromGeometry(Point.fromLngLat(-1., -1.)));
+    double[] bbox = TurfMeasurement.bbox(GeometryCollection.fromGeometries(geometries));
+
+    assertEquals(4, bbox.length);
+    assertEquals(-1, bbox[0], DELTA);
+    assertEquals(-10, bbox[1], DELTA);
+    assertEquals(130, bbox[2], DELTA);
+    assertEquals(4, bbox[3], DELTA);
+  }
 }

services-turf/src/test/resources/turf-bbox/multipoint.geojson

@@ -0,0 +1,21 @@
+{
+  "type": "MultiPoint",
+  "coordinates": [
+    [
+      102,
+      -10
+    ],
+    [
+      103,
+      1
+    ],
+    [
+      104,
+      0
+    ],
+    [
+      130,
+      4
+    ]
+  ]
+}