Identify KML features

View on GitHub
Sample viewer app

Show a callout with formatted content for a KML feature.

Image of identify KML features

Use case

A user may wish to select a KML feature to view relevant information about it.

How to use the sample

Click on a feature to identify it. Feature information will be displayed in a callout.

Note: the KML layer used in this sample contains a screen overlay. The screen overlay contains a legend and the logos for NOAA and the NWS. You can't identify the screen overlay.

How it works

  1. Listen to clicks on the MapView using setOnMouseClicked().
  2. When the map view is clicked:
  3. Dismiss the Callout, if one is showing.
  4. Call identifyLayerAsync(...) passing in the KmlLayer, screen point and tolerance.
  5. Await the result of the identify and then get the KmlPlacemark from the result.
  6. Create a callout at the calculated map point and populate the callout content with text from the placemark's "balloon content". NOTE: KML supports defining HTML for balloon content and may need to be converted from HTML to text.
  7. Show the callout.

Note: There are several types of KML features. This sample only identifies features of type KmlPlacemark.

Relevant API

  • IdentifyLayerResult
  • KmlLayer
  • KmlPlacemark
  • MapView

About the data

This sample shows a forecast for significant weather within the U.S. Regions of severe thunderstorms, flooding, snowfall, and freezing rain are shown.

Additional information

KML features can have rich HTML content, including images.

Tags

Keyhole, KML, KMZ, NOAA, NWS, OGC, weather

Sample Code

IdentifyKMLFeaturesSample.java
                                                                                                                                                            
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/*
 * 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.identify_kml_features;

import java.util.concurrent.ExecutionException;

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

import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.geometry.Envelope;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.layers.KmlLayer;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.GeoElement;
import com.esri.arcgisruntime.mapping.view.IdentifyLayerResult;
import com.esri.arcgisruntime.mapping.view.MapView;
import com.esri.arcgisruntime.ogc.kml.KmlDataset;
import com.esri.arcgisruntime.ogc.kml.KmlPlacemark;

public class IdentifyKMLFeaturesSample extends Application {

  private MapView mapView;

  @Override
  public void start(Stage stage) {

    try {
      // create stack pane and application scene
      StackPane stackPane = new StackPane();
      Scene scene = new Scene(stackPane);

      // set title, size, and add scene to stage
      stage.setTitle("Identify KML Features 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 map with the dark gray basemap style
      ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_DARK_GRAY);

      // create a map view and set the map to it
      mapView = new MapView();
      mapView.setMap(map);

      // start zoomed in over the US
      mapView.setViewpointGeometryAsync(new Envelope(-19195297.778679, 512343.939994, -3620418.579987, 8658913.035426, 0.0, 0.0, SpatialReferences.getWebMercator()));

      // create a KML dataset of weather forecasts
      KmlDataset forecastDataset = new KmlDataset("https://www.wpc.ncep.noaa.gov/kml/noaa_chart/WPC_Day1_SigWx_latest.kml");

      // create a KML layer and add it as an operational layer
      KmlLayer forecastLayer = new KmlLayer(forecastDataset);
      map.getOperationalLayers().add(forecastLayer);

      // add a click listener to identify clicked features
      mapView.setOnMouseClicked(e -> {
        // hide the callout if it's showing
        mapView.getCallout().dismiss();

        if (e.isStillSincePress() && e.getButton() == MouseButton.PRIMARY) {
          // get the identified geoelements at the clicked location
          Point2D screenPoint = new Point2D(e.getX(), e.getY());
          ListenableFuture<IdentifyLayerResult> identify = mapView.identifyLayerAsync(forecastLayer, screenPoint, 15, false);
          identify.addDoneListener(() -> {
            try {
              IdentifyLayerResult result = identify.get();
              // find the first geoElement that is a KML placemark
              for (GeoElement geoElement : result.getElements()) {
                if (geoElement instanceof KmlPlacemark) {
                  // show a callout at the placemark with custom content using the placemark's "balloon content"
                  KmlPlacemark placemark = (KmlPlacemark) geoElement;

                  // Google Earth only displays the placemarks with description or extended data. To
                  // match its behavior, add a description placeholder if the data source is empty
                  if (placemark.getDescription().isEmpty()) {
                    placemark.setDescription("Weather condition");
                  }

                  VBox vBox = new VBox();
                  WebView webView = new WebView();
                  webView.setMaxSize(400, 100);
                  webView.getEngine().loadContent(placemark.getBalloonContent());
                  vBox.getChildren().add(webView);
                  mapView.getCallout().setCustomView(vBox);
                  Point interactionPoint = mapView.screenToLocation(screenPoint);
                  mapView.getCallout().showCalloutAt(geoElement, interactionPoint);
                  break;
                }
              }
            } catch (InterruptedException | ExecutionException ex) {
              new Alert(Alert.AlertType.ERROR, "Error identifying features in layer").show();
            }
          });
        }
      });

      // add the map view to stack pane
      stackPane.getChildren().add(mapView);
    } 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 (mapView != null) {
      mapView.dispose();
    }
  }

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

    Application.launch(args);
  }

}

Your browser is no longer supported. Please upgrade your browser for the best experience. See our browser deprecation post for more details.