Find the union, difference, or intersection of two geometries.

Use case
Determining the spatial relationships between points, lines or polygons is a fundamental concept in GIS. For example, a data analyst may need to find the intersection between areas with a high concentration of medical emergency situations and the service area of a hospital.
How to use the sample
The sample provides a drop down on the top, where you can select a geometry operation. When you choose a geometry operation, the application performs this operation between the overlapping polygons and applies the result to the geometries.
How it works
- Get the
Geometryof the features you would like to perform a spatial operation on. - Use the various static methods of
GeometryEngineto determine the spatial relationships between the geometries. For example, useGeometryEngine.intersection(polygon1.getGeometry(), polygon2.getGeometry())to find the intersection between two polygons.
Relevant API
- Geometry
- Graphic
- GraphicsOverlay
- MapView
- Point
- PointCollection
- SimpleLineSymbol
- SimpleFillSymbol
Tags
combine, difference, edit, intersect, intersection, modify, symmetric difference, union
Sample Code
/* * Copyright 2022 Esri. * * Licensed 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. */
module com.esri.samples.spatial_operations { // require ArcGIS Maps SDK for Java module requires com.esri.arcgisruntime;
// handle SLF4J http://www.slf4j.org/codes.html#StaticLoggerBinder requires org.slf4j.nop;
// require JavaFX modules that the application uses requires javafx.graphics; requires javafx.controls;
exports com.esri.samples.spatial_operations;}/* * Copyright 2017 Esri. * * Licensed 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 com.esri.samples.spatial_operations;
import javafx.application.Application;import javafx.collections.FXCollections;import javafx.geometry.Insets;import javafx.geometry.Pos;import javafx.scene.Scene;import javafx.scene.control.Alert;import javafx.scene.control.ComboBox;import javafx.scene.layout.StackPane;import javafx.scene.paint.Color;import javafx.stage.Stage;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;import com.esri.arcgisruntime.geometry.Geometry;import com.esri.arcgisruntime.geometry.GeometryEngine;import com.esri.arcgisruntime.geometry.Part;import com.esri.arcgisruntime.geometry.PartCollection;import com.esri.arcgisruntime.geometry.Point;import com.esri.arcgisruntime.geometry.PointCollection;import com.esri.arcgisruntime.geometry.Polygon;import com.esri.arcgisruntime.geometry.SpatialReferences;import com.esri.arcgisruntime.loadable.LoadStatus;import com.esri.arcgisruntime.mapping.ArcGISMap;import com.esri.arcgisruntime.mapping.BasemapStyle;import com.esri.arcgisruntime.mapping.view.Graphic;import com.esri.arcgisruntime.mapping.view.GraphicsOverlay;import com.esri.arcgisruntime.mapping.view.MapView;import com.esri.arcgisruntime.symbology.SimpleFillSymbol;import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
public class SpatialOperationsSample extends Application {
private ArcGISMap map; // keep loadable in scope to avoid garbage collection private MapView mapView; private GraphicsOverlay resultGeomOverlay; private Graphic polygon1; private Graphic polygon2;
// geometry operations private enum OPERATION_TYPE { NONE, UNION, DIFFERENCE, SYMMETRIC_DIFFERENCE, INTERSECTION }
// simple black line symbol private final SimpleLineSymbol line = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, Color.BLACK, 1);
@Override public void start(Stage stage) {
try { // create stack pane and application scene StackPane stackPane = new StackPane(); Scene scene = new Scene(stackPane); scene.getStylesheets().add(getClass().getResource("/spatial_operations/style.css").toExternalForm());
// set title, size, and add scene to stage stage.setTitle("Spatial Operations Sample"); stage.setWidth(800); stage.setHeight(700); stage.setScene(scene); stage.show();
// authentication with an API key or named user is required to access basemaps and other location services String yourAPIKey = System.getProperty("apiKey"); ArcGISRuntimeEnvironment.setApiKey(yourAPIKey);
// initialise comboBox items ComboBox<OPERATION_TYPE> geomOperationBox = new ComboBox<>(FXCollections.observableArrayList(OPERATION_TYPE .values())); geomOperationBox.getSelectionModel().select(OPERATION_TYPE.NONE); geomOperationBox.setMaxWidth(180); geomOperationBox.setDisable(true);
// handle ComboBox event to perform the selected geometry operation geomOperationBox.setOnAction(e -> { resultGeomOverlay.getGraphics().clear(); Geometry resultPolygon; switch (geomOperationBox.getSelectionModel().getSelectedItem()) { case UNION: resultPolygon = GeometryEngine.union(polygon1.getGeometry(), polygon2.getGeometry()); break; case DIFFERENCE: resultPolygon = GeometryEngine.difference(polygon1.getGeometry(), polygon2.getGeometry()); break; case SYMMETRIC_DIFFERENCE: resultPolygon = GeometryEngine.symmetricDifference(polygon1.getGeometry(), polygon2.getGeometry()); break; case INTERSECTION: resultPolygon = GeometryEngine.intersection(polygon1.getGeometry(), polygon2.getGeometry()); break; case NONE: default: return; }
// update result as a red geometry SimpleFillSymbol redSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.RED, line); resultGeomOverlay.getGraphics().add(new Graphic(resultPolygon, redSymbol)); });
// create a map with the light gray basemap style map = new ArcGISMap(BasemapStyle.ARCGIS_LIGHT_GRAY);
// enable geometry operations when the map is done loading map.addDoneLoadingListener(() -> { if (map.getLoadStatus() == LoadStatus.LOADED) { geomOperationBox.setDisable(false); } else { Alert alert = new Alert(Alert.AlertType.ERROR, "Map Failed to Load!"); alert.show(); } });
// create a map view and set the map to it mapView = new MapView(); mapView.setMap(map);
// set a viewpoint on the map view centered on London mapView.setViewpointCenterAsync(new Point(-14153, 6710527, SpatialReferences.getWebMercator()), 30000);
// create geometry overlays GraphicsOverlay geomOverlay = new GraphicsOverlay(); mapView.getGraphicsOverlays().add(geomOverlay);
resultGeomOverlay = new GraphicsOverlay(); mapView.getGraphicsOverlays().add(resultGeomOverlay);
// create sample polygons createPolygons();
geomOverlay.getGraphics().add(polygon1); geomOverlay.getGraphics().add(polygon2);
// add the map view and control panel to stack pane stackPane.getChildren().addAll(mapView, geomOperationBox); StackPane.setAlignment(geomOperationBox, Pos.TOP_LEFT); StackPane.setMargin(geomOperationBox, new Insets(10, 0, 0, 10));
} catch (Exception e) { // on any error, display the stack trace e.printStackTrace(); } }
/** * Creates the two intersecting polygons used in the application. */ private void createPolygons() {
// create blue polygon PointCollection pointsPoly = new PointCollection(SpatialReferences.getWebMercator()); pointsPoly.add(new Point(-13960, 6709400)); pointsPoly.add(new Point(-14660, 6710000)); pointsPoly.add(new Point(-13760, 6710730)); pointsPoly.add(new Point(-13300, 6710500)); pointsPoly.add(new Point(-13160, 6710100));
SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.BLUE, line); Polygon polygonSymbol = new Polygon(pointsPoly); polygon1 = new Graphic(polygonSymbol, fillSymbol);
// create green polygon // outer ring PointCollection outerRingSegmentCollection = new PointCollection(SpatialReferences.getWebMercator()); outerRingSegmentCollection.add(new Point(-13060, 6711030)); outerRingSegmentCollection.add(new Point(-12160, 6710730)); outerRingSegmentCollection.add(new Point(-13160, 6709700)); outerRingSegmentCollection.add(new Point(-14560, 6710730)); Part outerRing = new Part(outerRingSegmentCollection);
// inner ring PointCollection innerRingSegmentCollection = new PointCollection(SpatialReferences.getWebMercator()); innerRingSegmentCollection.add(new Point(-13060, 6710910)); innerRingSegmentCollection.add(new Point(-14160, 6710630)); innerRingSegmentCollection.add(new Point(-13160, 6709900)); innerRingSegmentCollection.add(new Point(-12450, 6710660)); Part innerRing = new Part(innerRingSegmentCollection);
PartCollection polygonParts = new PartCollection(outerRing); polygonParts.add(innerRing); fillSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.GREEN, line); polygon2 = new Graphic(new Polygon(polygonParts), fillSymbol); }
/** * Stops and releases all resources used in application. */ @Override public void stop() {
if (mapView != null) { mapView.dispose(); } }
/** * Opens and runs application. * * @param args arguments passed to this application */ public static void main(String[] args) {
Application.launch(args); }}