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
GeometryEngineSimplifySample.java
/* * 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); } }