Viewshed location

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Sample viewer app

Perform a viewshed analysis from a defined vantage point.

Image of viewshed location

Use case

A 3D viewshed analysis is a type of visual analysis you can perform on a scene. The viewshed shows what can be seen from a given location. The output is an overlay with two different colors - one representing the visible areas (green) and the other representing the obstructed areas (red). Viewshed analysis is a form of "exploratory analysis", which means the results are calculated on the current scale of the data, and the results are generated very quickly. If more "conclusive" results are required, consider using a GeoprocessingTask to perform a viewshed instead.

How to use the sample

Use the sliders to change the properties (heading, pitch, etc.), of the viewshed and see them updated in real time. To move the viewshed, click on the scene and move your mouse. Click again to stop moving the viewshed.

How it works

  1. Create a LocationViewshed passing in the observer location, heading, pitch, horizontal/vertical angles, and min/max distances.
  2. Set the property values on the viewshed instance for location, direction, range, and visibility properties.

Relevant API

  • AnalysisOverlay
  • ArcGISSceneLayer
  • ArcGISTiledElevationSource
  • LocationViewshed
  • Viewshed

About the data

The scene shows a buildings layer in Brest, France hosted on ArcGIS Online.

Tags

3D, frustum, scene, viewshed, visibility analysis

Sample Code

ViewshedLocationController.javaViewshedLocationSample.javamain.fxml
                                                                                                                                                                 
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/*
 * 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.viewshed_location;

import java.util.concurrent.ExecutionException;

import javafx.beans.binding.Bindings;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.geometry.Point2D;
import javafx.scene.control.Slider;
import javafx.scene.control.ToggleButton;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;

import com.esri.arcgisruntime.geoanalysis.LocationViewshed;
import com.esri.arcgisruntime.geoanalysis.Viewshed;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.PointBuilder;
import com.esri.arcgisruntime.layers.ArcGISSceneLayer;
import com.esri.arcgisruntime.mapping.ArcGISScene;
import com.esri.arcgisruntime.mapping.ArcGISTiledElevationSource;
import com.esri.arcgisruntime.mapping.Basemap;
import com.esri.arcgisruntime.mapping.Surface;
import com.esri.arcgisruntime.mapping.view.AnalysisOverlay;
import com.esri.arcgisruntime.mapping.view.Camera;
import com.esri.arcgisruntime.mapping.view.SceneView;

public class ViewshedLocationController {

  @FXML private SceneView sceneView;
  @FXML private ToggleButton visibilityToggle;
  @FXML private ToggleButton frustumToggle;
  @FXML private Slider headingSlider;
  @FXML private Slider pitchSlider;
  @FXML private Slider horizontalAngleSlider;
  @FXML private Slider verticalAngleSlider;
  @FXML private Slider minDistanceSlider;
  @FXML private Slider maxDistanceSlider;

  public void initialize() {
    // create a scene and add a basemap to it
    ArcGISScene scene = new ArcGISScene();
    scene.setBasemap(Basemap.createImagery());
    sceneView.setArcGISScene(scene);

    // add base surface for elevation data
    Surface surface = new Surface();
    final String localElevationImageService = "http://scene.arcgis" +
        ".com/arcgis/rest/services/BREST_DTM_1M/ImageServer";
    surface.getElevationSources().add(new ArcGISTiledElevationSource(localElevationImageService));
    scene.setBaseSurface(surface);

    // add a scene layer
    final String buildings = "http://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Brest/SceneServer/layers/0";
    ArcGISSceneLayer sceneLayer = new ArcGISSceneLayer(buildings);
    scene.getOperationalLayers().add(sceneLayer);

    // create a viewshed from the camera
    Point location = new Point(-4.50, 48.4,100.0);
    LocationViewshed viewshed = new LocationViewshed(location, headingSlider.getValue(), pitchSlider.getValue(),
        horizontalAngleSlider.getValue(), verticalAngleSlider.getValue(), minDistanceSlider.getValue(),
        maxDistanceSlider.getValue());
    // set the colors of the visible and obstructed areas
    Viewshed.setVisibleColor(0xCC00FF00);
    Viewshed.setObstructedColor(0xCCFF0000);
    // set the color and show the frustum outline
    Viewshed.setFrustumOutlineColor(0xCC0000FF);
    viewshed.setFrustumOutlineVisible(true);

    // set the camera
    Camera camera = new Camera(location, 200.0, 20.0, 70.0, 0.0);
    sceneView.setViewpointCamera(camera);

    // create an analysis overlay to add the viewshed to the scene view
    AnalysisOverlay analysisOverlay = new AnalysisOverlay();
    analysisOverlay.getAnalyses().add(viewshed);
    sceneView.getAnalysisOverlays().add(analysisOverlay);

    // create a listener to update the viewshed location when the mouse moves
    EventHandler<MouseEvent> mouseMoveEventHandler = new EventHandler<MouseEvent>() {
      @Override
      public void handle(MouseEvent event) {
        Point2D point2D = new Point2D(event.getX(), event.getY());
        ListenableFuture<Point> pointFuture = sceneView.screenToLocationAsync(point2D);
        pointFuture.addDoneListener(() -> {
          try {
            Point point = pointFuture.get();
            PointBuilder pointBuilder = new PointBuilder(point);
            pointBuilder.setZ(point.getZ() + 50.0);
            viewshed.setLocation(pointBuilder.toGeometry());
            // add listener back
            sceneView.setOnMouseMoved(this);
          } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
          }
        });
        // disable listener until location is updated (for performance)
        sceneView.setOnMouseMoved(null);
      }
    };
    // remove the default listener for mouse move events
    sceneView.setOnMouseMoved(null);

    // click to start/stop moving viewshed with mouse
    sceneView.setOnMouseClicked(event -> {
      if (event.isStillSincePress() && event.getButton() == MouseButton.PRIMARY) {
        if (sceneView.getOnMouseMoved() == null) {
          sceneView.setOnMouseMoved(mouseMoveEventHandler);
        } else {
          sceneView.setOnMouseMoved(null);
        }
      }
    });

    // toggle visibility
    visibilityToggle.selectedProperty().addListener(e -> viewshed.setVisible(visibilityToggle.isSelected()));
    visibilityToggle.textProperty().bind(Bindings.createStringBinding(() -> visibilityToggle.isSelected() ? "ON" :
        "OFF", visibilityToggle.selectedProperty()));
    frustumToggle.selectedProperty().addListener(e -> viewshed.setFrustumOutlineVisible(frustumToggle.isSelected()));
    frustumToggle.textProperty().bind(Bindings.createStringBinding(() -> frustumToggle.isSelected() ? "ON" :
        "OFF", frustumToggle.selectedProperty()));
    // heading slider
    headingSlider.valueProperty().addListener(e -> viewshed.setHeading(headingSlider.getValue()));
    // pitch slider
    pitchSlider.valueProperty().addListener(e -> viewshed.setPitch(pitchSlider.getValue()));
    // horizontal angle slider
    horizontalAngleSlider.valueProperty().addListener(e -> viewshed.setHorizontalAngle(horizontalAngleSlider.getValue()));
    // vertical angle slider
    verticalAngleSlider.valueProperty().addListener(e -> viewshed.setVerticalAngle(verticalAngleSlider
        .getValue()));
    // distance sliders
    minDistanceSlider.valueProperty().addListener(e -> viewshed.setMinDistance(minDistanceSlider.getValue()));
    maxDistanceSlider.valueProperty().addListener(e -> viewshed.setMaxDistance(maxDistanceSlider.getValue()));
  }

  /**
   * Stops the animation and disposes of application resources.
   */
  void terminate() {

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

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