Simplify a polygon with a self-intersecting geometry.

Use case
A user may draw a polygon which is self-intersecting or contains incorrect ring orientations. The geometry must be simplified before it can be saved to a geodatabase.
How to use the sample
Click the ‘Simplify’ button to simplify the geometry. Click ‘Reset’ to reset to the original geometry.
How it works
- Check if the polygon geometry needs to be simplified using
GeometryEngine.isSimple(Geometry). - Simplify the polygon’s geometry using
GeometryEngine.simplify(Geometry).
Relevant API
- Geometry
- GeometryEngine
Additional information
The concept of topological simplicity is different than geometry generalization, where points are removed from polygons or lines to create a more generalized result while preserving overall shape. See the ‘Densify and Generalize’ sample for comparison.
Tags
geometry, polygon, simplify, spatial operations, topology
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.geometry_engine_simplify { // 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.geometry_engine_simplify;}/* * 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.geometry_engine_simplify;
import javafx.application.Application;import javafx.geometry.Insets;import javafx.geometry.Pos;import javafx.scene.Scene;import javafx.scene.control.Alert;import javafx.scene.control.Button;import javafx.scene.layout.Background;import javafx.scene.layout.BackgroundFill;import javafx.scene.layout.CornerRadii;import javafx.scene.layout.StackPane;import javafx.scene.layout.VBox;import javafx.scene.paint.Color;import javafx.scene.paint.Paint;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 GeometryEngineSimplifySample extends Application {
private ArcGISMap map; // keep loadable in scope to avoid garbage collection private GraphicsOverlay resultGeomOverlay; private Graphic polygon; private MapView mapView;
// 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("/geometry_engine_simplify/style.css").toExternalForm());
// set title, size, and add scene to stage stage.setTitle("Geometry Engine Simplify 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);
// create a control panel VBox controlsVBox = new VBox(6); controlsVBox.setBackground(new Background(new BackgroundFill(Paint.valueOf("rgba(0,0,0,0.3)"), CornerRadii.EMPTY, Insets.EMPTY))); controlsVBox.setPadding(new Insets(10.0)); controlsVBox.setMaxSize(110, 80); controlsVBox.getStyleClass().add("panel-region");
// create simplify button Button simplifyButton = new Button("Simplify"); simplifyButton.setMaxWidth(Double.MAX_VALUE); simplifyButton.setDisable(true);
// create reset button Button resetButton = new Button("Reset"); resetButton.setMaxWidth(Double.MAX_VALUE); resetButton.setDisable(true);
// perform the simplify geometry operation simplifyButton.setOnAction(e -> {
// check if the geometry needs to be simplified if (!GeometryEngine.isSimple(polygon.getGeometry())) {
// simplify the geometry Geometry resultPolygon = GeometryEngine.simplify(polygon.getGeometry());
// update result as a red graphic SimpleFillSymbol redSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.RED, line); resultGeomOverlay.getGraphics().add(new Graphic(resultPolygon, redSymbol));
resetButton.setDisable(false); simplifyButton.setDisable(true); } });
// clear result layer resetButton.setOnAction(e -> { resultGeomOverlay.getGraphics().clear(); simplifyButton.setDisable(false); resetButton.setDisable(true); });
// add buttons to the control panel controlsVBox.getChildren().addAll(simplifyButton, resetButton);
// 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) { simplifyButton.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(-13500, 6710327, SpatialReferences.getWebMercator()), 25000);
// create geometry layers GraphicsOverlay geomOverlay = new GraphicsOverlay(); mapView.getGraphicsOverlays().add(geomOverlay);
resultGeomOverlay = new GraphicsOverlay(); mapView.getGraphicsOverlays().add(resultGeomOverlay);
// create sample polygon createPolygon(); geomOverlay.getGraphics().add(polygon);
// add the map view and control panel to stack pane stackPane.getChildren().addAll(mapView, controlsVBox); StackPane.setAlignment(controlsVBox, Pos.TOP_LEFT); StackPane.setMargin(controlsVBox, new Insets(10, 0, 0, 10));
} catch (Exception e) { // on any error, display the stack trace e.printStackTrace(); } }
/** * Creates the polygon. */ private void createPolygon() {
// part one PointCollection partSegmentCollectionOne = new PointCollection(SpatialReferences.getWebMercator()); partSegmentCollectionOne.add(new Point(-13020, 6710130)); partSegmentCollectionOne.add(new Point(-14160, 6710130)); partSegmentCollectionOne.add(new Point(-14160, 6709300)); partSegmentCollectionOne.add(new Point(-13020, 6709300)); partSegmentCollectionOne.add(new Point(-13020, 6710130)); Part partOne = new Part(partSegmentCollectionOne);
// part two PointCollection partSegmentCollectionTwo = new PointCollection(SpatialReferences.getWebMercator()); partSegmentCollectionTwo.add(new Point(-12160, 6710730)); partSegmentCollectionTwo.add(new Point(-13160, 6710730)); partSegmentCollectionTwo.add(new Point(-13160, 6709100)); partSegmentCollectionTwo.add(new Point(-12160, 6709100)); partSegmentCollectionTwo.add(new Point(-12160, 6710730)); Part partTwo = new Part(partSegmentCollectionTwo);
// part three PointCollection partSegmentCollectionThree = new PointCollection(SpatialReferences.getWebMercator()); partSegmentCollectionThree.add(new Point(-12560, 6710030)); partSegmentCollectionThree.add(new Point(-13520, 6710030)); partSegmentCollectionThree.add(new Point(-13520, 6709000)); partSegmentCollectionThree.add(new Point(-12560, 6709000)); partSegmentCollectionThree.add(new Point(-12560, 6710030)); Part partThree = new Part(partSegmentCollectionThree);
PartCollection polygonParts = new PartCollection(partOne); polygonParts.add(partTwo); polygonParts.add(partThree);
// transparent fill SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.TRANSPARENT, line); polygon = 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); }}