Get elevation at a point

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/*
 * Copyright 2019 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.get_elevation_at_a_point;

import java.util.concurrent.ExecutionException;

import javafx.application.Application;
import javafx.geometry.Point2D;
import javafx.scene.control.Alert;
import javafx.scene.input.MouseButton;
import javafx.scene.layout.StackPane;
import javafx.scene.Scene;
import javafx.stage.Stage;

import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.Polyline;
import com.esri.arcgisruntime.geometry.PolylineBuilder;
import com.esri.arcgisruntime.mapping.ArcGISScene;
import com.esri.arcgisruntime.mapping.ArcGISTiledElevationSource;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Surface;
import com.esri.arcgisruntime.mapping.view.Camera;
import com.esri.arcgisruntime.mapping.view.Graphic;
import com.esri.arcgisruntime.mapping.view.GraphicsOverlay;
import com.esri.arcgisruntime.mapping.view.LayerSceneProperties;
import com.esri.arcgisruntime.mapping.view.SceneView;
import com.esri.arcgisruntime.symbology.TextSymbol;
import com.esri.arcgisruntime.symbology.SimpleLineSymbol;

public class GetElevationAtAPointSample extends Application {

  private SceneView sceneView;
  private GraphicsOverlay graphicsOverlay;

  @Override
  public void start(Stage stage) {

    try {
      // create stack pane and application scene
      StackPane stackPane = new StackPane();
      Scene fxScene = new Scene(stackPane);
      fxScene.getStylesheets().add(getClass().getResource("/get_elevation_at_a_point/style.css").toExternalForm());

      // set title, size, and add JavaFX scene to stage
      stage.setTitle("Get Elevation at a Point Sample");
      stage.setWidth(800);
      stage.setHeight(700);
      stage.setScene(fxScene);
      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 scene with a basemap style
      ArcGISScene scene = new ArcGISScene(BasemapStyle.ARCGIS_IMAGERY);

      // add the SceneView to the stack pane
      sceneView = new SceneView();
      sceneView.setArcGISScene(scene);
      stackPane.getChildren().add(sceneView);

      // add base surface for elevation data
      Surface surface = new Surface();
      surface.getElevationSources().add(new ArcGISTiledElevationSource("https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"));
      scene.setBaseSurface(surface);

      // create a point symbol and graphic to mark where elevation is being measured
      SimpleLineSymbol elevationLineSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, 0xFFFF0000, 3.0f);
      Graphic polylineGraphic = new Graphic();
      polylineGraphic.setSymbol(elevationLineSymbol);

      // create a text symbol and graphic to display the elevation of selected points
      TextSymbol elevationTextSymbol = new TextSymbol(20, null, 0xFFFF0000, TextSymbol.HorizontalAlignment.CENTER, TextSymbol.VerticalAlignment.BOTTOM);
      Graphic elevationTextGraphic = new Graphic();
      elevationTextGraphic.setSymbol(elevationTextSymbol);

      // create a graphics overlay
      graphicsOverlay = new GraphicsOverlay(GraphicsOverlay.RenderingMode.DYNAMIC);
      graphicsOverlay.getSceneProperties().setSurfacePlacement(LayerSceneProperties.SurfacePlacement.RELATIVE);
      sceneView.getGraphicsOverlays().add(graphicsOverlay);

      // add a camera and initial camera position
      Camera camera = new Camera(28.42, 83.9, 10000.0, 10.0, 80.0, 0.0);
      sceneView.setViewpointCamera(camera);

      // create listener to handle clicks
      sceneView.setOnMouseClicked(event -> {
        if (event.getButton() == MouseButton.PRIMARY && event.isStillSincePress()) {
          // get the clicked screenPoint
          Point2D screenPoint = new Point2D(event.getX(), event.getY());
          // convert the screen point to a point on the surface
          Point relativeSurfacePoint = sceneView.screenToBaseSurface(screenPoint);

          // check that the point is on the surface
          if (relativeSurfacePoint != null) {

            // clear any existing graphics from the graphics overlay
            graphicsOverlay.getGraphics().clear();

            // construct a polyline to use as a marker
            PolylineBuilder polylineBuilder = new PolylineBuilder(relativeSurfacePoint.getSpatialReference());
            Point baseOfPolyline = new Point(relativeSurfacePoint.getX(), relativeSurfacePoint.getY(), 0);
            polylineBuilder.addPoint(baseOfPolyline);
            Point topOfPolyline = new Point(baseOfPolyline.getX(), baseOfPolyline.getY(), 750);
            polylineBuilder.addPoint(topOfPolyline);
            Polyline markerPolyline = polylineBuilder.toGeometry();
            polylineGraphic.setGeometry(markerPolyline);
            graphicsOverlay.getGraphics().add(polylineGraphic);

            // get the surface elevation at the surface point
            ListenableFuture<Double> elevationFuture = scene.getBaseSurface().getElevationAsync(relativeSurfacePoint);
            elevationFuture.addDoneListener(() -> {
              try {
                // get the surface elevation
                Double elevation = elevationFuture.get();

                // update the text in the elevation marker
                elevationTextSymbol.setText(Math.round(elevation) + " m");
                elevationTextGraphic.setGeometry(topOfPolyline);
                graphicsOverlay.getGraphics().add(elevationTextGraphic);

              } catch (InterruptedException | ExecutionException e) {
                new Alert(Alert.AlertType.ERROR, e.getCause().getMessage()).show();
              }
            });
          }
        }
      });
    } catch (Exception e) {
      // on any error, display the stack trace.
      e.printStackTrace();
    }
  }

  /**
   * Stops and releases all resources used in application.
   */
  @Override
  public void stop() {

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

  /**
   * Opens and runs application.
   *
   * @param args arguments passed to this application
   */
  public static void main(String[] args) {

    Application.launch(args);
  }

}