Geodesic sector and ellipse

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Create and display geodesic sectors and ellipses.

Image of geodesic sector and ellipse

Use case

Geodesic sectors and ellipses can be used in a wide range of analyses ranging from projectile landing zones to antenna coverage. For example, given the strength and direction of a cellular tower's signal, you could generate cell coverage geometries to identify areas without sufficient connectivity.

How to use the sample

The geodesic sector and ellipse will display with default parameters at the start. Click anywhere on the map to change the center of the geometries. Adjust any of the controls to see how they affect the sector and ellipse on the fly.

How it works

  1. Create GeodesicSectorParameters and GeodesicEllipseParameters using one of the constructors with default values or using each setter individually.
  2. Set the center, axisDirection, semiAxis1Length, and the semiAxis2Length properties to change the general ellipse position, shape, and orientation.
  3. Set the sectorAngle and startDirection angles to change the sector's shape and orientation.
  4. Set the maxPointCount and maxSegmentLength properties to control the complexity of the geometries and the approximation of the ellipse curve.
  5. Specify the geometryType to either POLYGON, POLYLINE, or MULTIPOINT to change the result geometry type.
  6. Pass the parameters to the related static methods: GeometryEngine.ellipseGeodesic(geodesicEllipseParameters) and GeometryEngine.sectorGeodesic(geodesicSectorParameters). The returned value will be a Geometry of the type specified by the geometryType parameter.

Relevant API

  • GeodesicEllipseParameters
  • GeodesicSectorParameters
  • GeometryEngine
  • GeometryType

Additional information

To create a circle instead of an ellipse, simply set semiAxis2Length to 0.0 and semiAxis1Length to the desired radius of the circle. This eliminates the need to update both parameters to the same value.

Tags

ellipse, geodesic, geometry, sector

Sample Code

GeodesicSectorAndEllipseController.javaGeodesicSectorAndEllipseSample.javamain.fxml
                                                                                                                                                                                             
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/*
 * Copyright 2018 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.geodesic_sector_and_ellipse;

import javafx.fxml.FXML;
import javafx.geometry.Point2D;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Slider;
import javafx.scene.control.Spinner;
import javafx.scene.input.MouseButton;

import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.geometry.GeodesicEllipseParameters;
import com.esri.arcgisruntime.geometry.GeodesicSectorParameters;
import com.esri.arcgisruntime.geometry.Geometry;
import com.esri.arcgisruntime.geometry.GeometryEngine;
import com.esri.arcgisruntime.geometry.GeometryType;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Viewpoint;
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.FillSymbol;
import com.esri.arcgisruntime.symbology.LineSymbol;
import com.esri.arcgisruntime.symbology.MarkerSymbol;
import com.esri.arcgisruntime.symbology.SimpleFillSymbol;
import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
import com.esri.arcgisruntime.symbology.SimpleMarkerSymbol;

public class GeodesicSectorAndEllipseController {

  @FXML private MapView mapView;
  @FXML private Slider axisDirectionSlider;
  @FXML private Spinner<Integer> maxPointCountSpinner;
  @FXML private Slider maxSegmentLengthSlider;
  @FXML private ComboBox<GeometryType> geometryTypeComboBox;
  @FXML private Slider sectorAngleSlider;
  @FXML private Slider semiAxis1LengthSlider;
  @FXML private Slider semiAxis2LengthSlider;
  @FXML private Slider startDirectionSlider;

  private Point center;
  private Graphic sectorGraphic;
  private Graphic ellipseGraphic;
  private FillSymbol sectorFillSymbol;
  private LineSymbol sectorLineSymbol;
  private MarkerSymbol sectorMarkerSymbol;

  public void initialize() {
    // 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 map with the standard imagery basemap style
    ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_IMAGERY_STANDARD);

    // set the map to the map view
    mapView.setMap(map);

    // set a viewpoint on the map view
    center = new Point(-13574921.207495, 4378809.903179, SpatialReferences.getWebMercator());
    mapView.setViewpoint(new Viewpoint(center, 10000));

    // create a graphics overlay for showing the geometries as graphics
    GraphicsOverlay graphicsOverlay = new GraphicsOverlay();
    mapView.getGraphicsOverlays().add(graphicsOverlay);

    // create a graphic to show the geodesic sector geometry
    sectorGraphic = new Graphic();
    graphicsOverlay.getGraphics().add(sectorGraphic);

    // create green symbols for each sector output geometry type
    sectorFillSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, 0x8800FF00, null);
    sectorLineSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, 0x8800FF00, 3);
    sectorMarkerSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.CIRCLE, 0x8800FF00, 3);

    // create a red dotted outline graph for showing the geodesic ellipse geometry
    SimpleLineSymbol ellipseLineSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.DOT, 0xFFFF0000, 2);
    ellipseGraphic = new Graphic();
    ellipseGraphic.setSymbol(ellipseLineSymbol);
    graphicsOverlay.getGraphics().add(ellipseGraphic);

    // set the center of the sector and ellipse where the user clicks on the map
    mapView.setOnMouseClicked(e -> {
      if (e.isStillSincePress() && e.getButton() == MouseButton.PRIMARY) {
        Point2D point2D = new Point2D(e.getX(), e.getY());
        center = mapView.screenToLocation(point2D);
        updateSector();
      }
    });

    // set up the controls with some default parameters
    GeodesicSectorParameters defaultParameters = new GeodesicSectorParameters(center, 100.0, 100.0, 15.0, 0.0);
    axisDirectionSlider.setValue(defaultParameters.getAxisDirection());
    maxPointCountSpinner.getValueFactory().setValue(Long.valueOf(defaultParameters.getMaxPointCount()).intValue());
    maxSegmentLengthSlider.setValue(defaultParameters.getMaxSegmentLength());
    geometryTypeComboBox.getItems().addAll(GeometryType.POLYGON, GeometryType.POLYLINE, GeometryType.MULTIPOINT);
    geometryTypeComboBox.getSelectionModel().select(GeometryType.POLYGON);
    sectorAngleSlider.setValue(defaultParameters.getSectorAngle());
    semiAxis1LengthSlider.setValue(defaultParameters.getSemiAxis1Length());
    semiAxis2LengthSlider.setValue(defaultParameters.getSemiAxis2Length());
    startDirectionSlider.setValue(defaultParameters.getStartDirection());

    // call updateSector when any of the controls change their value
    axisDirectionSlider.valueProperty().addListener(e -> updateSector());
    maxPointCountSpinner.valueProperty().addListener(e -> updateSector());
    maxSegmentLengthSlider.valueProperty().addListener(e -> updateSector());
    geometryTypeComboBox.valueProperty().addListener(e -> updateSector());
    sectorAngleSlider.valueProperty().addListener(e -> updateSector());
    semiAxis1LengthSlider.valueProperty().addListener(e -> updateSector());
    semiAxis2LengthSlider.valueProperty().addListener(e -> updateSector());
    startDirectionSlider.valueProperty().addListener(e -> updateSector());

    // update the sector with the default parameters
    updateSector();
  }

  /**
   * Updates the sector and ellipse graphics using the controls' values.
   */
  private void updateSector() {

    // create geodesic sector parameters
    GeodesicSectorParameters geodesicSectorParameters = new GeodesicSectorParameters();
    geodesicSectorParameters.setCenter(center);
    geodesicSectorParameters.setAxisDirection(axisDirectionSlider.getValue());
    geodesicSectorParameters.setMaxPointCount(maxPointCountSpinner.getValue());
    geodesicSectorParameters.setMaxSegmentLength(maxSegmentLengthSlider.getValue());
    geodesicSectorParameters.setGeometryType(geometryTypeComboBox.getSelectionModel().getSelectedItem());
    geodesicSectorParameters.setSectorAngle(sectorAngleSlider.getValue());
    geodesicSectorParameters.setSemiAxis1Length(semiAxis1LengthSlider.getValue());
    geodesicSectorParameters.setSemiAxis2Length(semiAxis2LengthSlider.getValue());
    geodesicSectorParameters.setStartDirection(startDirectionSlider.getValue());

    // create the geodesic sector parameter
    Geometry sectorGeometry = GeometryEngine.sectorGeodesic(geodesicSectorParameters);
    // set the sector graphic's geometry to the sector
    sectorGraphic.setGeometry(sectorGeometry);
    // update the graphic's symbol depending on the chosen output geometry type
    switch (sectorGeometry.getGeometryType()) {
      case MULTIPOINT:
        sectorGraphic.setSymbol(sectorMarkerSymbol);
        break;
      case POLYGON:
        sectorGraphic.setSymbol(sectorFillSymbol);
        break;
      case POLYLINE:
        sectorGraphic.setSymbol(sectorLineSymbol);
        break;
    }

    // create geodesic ellipse parameters using the same values from the geodesic sector parameters
    // use one of the constructors that sets some defaults for you
    GeodesicEllipseParameters geodesicEllipseParameters = new GeodesicEllipseParameters(center, semiAxis1LengthSlider
        .getValue(), semiAxis2LengthSlider.getValue());
    geodesicEllipseParameters.setAxisDirection(axisDirectionSlider.getValue());
    // show the geodesic ellipse that the sector is in
    Geometry ellipseGeometry = GeometryEngine.ellipseGeodesic(geodesicEllipseParameters);
    ellipseGraphic.setGeometry(ellipseGeometry);
  }

  /**
   * Disposes of application resources.
   */
  void terminate() {

    if (mapView != null) {
      mapView.dispose();
    }
  }

}

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