Source: layer/OpenStreetMapImageLayer.js

  1. /*
  2.  * Copyright 2003-2006, 2009, 2017, 2020 United States Government, as represented
  3.  * by the Administrator of the National Aeronautics and Space Administration.
  4.  * All rights reserved.
  5.  *
  6.  * The NASAWorldWind/WebWorldWind platform is licensed under the Apache License,
  7.  * Version 2.0 (the "License"); you may not use this file except in compliance
  8.  * with the License. You may obtain a copy of the License
  9.  * at http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software distributed
  12.  * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
  13.  * CONDITIONS OF ANY KIND, either express or implied. See the License for the
  14.  * specific language governing permissions and limitations under the License.
  15.  *
  16.  * NASAWorldWind/WebWorldWind also contains the following 3rd party Open Source
  17.  * software:
  18.  *
  19.  *    ES6-Promise – under MIT License
  20.  *    libtess.js – SGI Free Software License B
  21.  *    Proj4 – under MIT License
  22.  *    JSZip – under MIT License
  23.  *
  24.  * A complete listing of 3rd Party software notices and licenses included in
  25.  * WebWorldWind can be found in the WebWorldWind 3rd-party notices and licenses
  26.  * PDF found in code  directory.
  27.  */
  28. /**
  29.  * @exports OpenStreetMapImageLayer
  30.  */
  31. define([
  32.         '../util/Color',
  33.         '../layer/Layer',
  34.         '../util/Logger',
  35.         '../ogc/wmts/WmtsCapabilities',
  36.         '../layer/WmtsLayer'
  37.     ],
  38.     function (Color,
  39.               Layer,
  40.               Logger,
  41.               WmtsCapabilities,
  42.               WmtsLayer) {
  43.         "use strict";
  45.         /**
  46.          * Constructs an Open Street Map layer.
  47.          * @alias OpenStreetMapImageLayer
  48.          * @constructor
  49.          * @augments WmtsLayer
  50.          * @classdesc Provides a layer that shows Open Street Map imagery.
  51.          *
  52.          * @param {String} displayName This layer's display name. "Open Street Map" if this parameter is
  53.          * null or undefined.
  54.          */
  55.         var OpenStreetMapImageLayer = function (displayName) {
  57.             Layer.call(this, this.displayName);
  59.             this.displayName = displayName || "Open Street Map";
  61.             this.layer = null;
  63.             this.xhr = null;
  65.             // TODO: Picking is enabled as a temporary measure for screen credit hyperlinks to work (see Layer.render)
  66.             this.pickEnabled = true;
  67.         };
  69.         OpenStreetMapImageLayer.prototype = Object.create(Layer.prototype);
  71.         OpenStreetMapImageLayer.prototype.doRender = function (dc) {
  73.             this.configureLayer(dc);
  75.             if (this.layer) {
  76.                 this.layer.opacity = this.opacity;
  77.                 this.layer.doRender(dc);
  78.                 this.inCurrentFrame = this.layer.inCurrentFrame;
  80.                 // Add a screen credit to attribute the data source to OSM and EOX
  81.                 // The pattern for this attribute is described in the WMTS Capabilities document and demonstrated at EOX
  82.                 // Maps site: http://maps.eox.at/
  83.                 if (this.inCurrentFrame) {
  84.                     dc.screenCreditController.addCredit("OpenStreetMap ©", Color.DARK_GRAY);
  85.                     dc.screenCreditController.addCredit("EOX.at ©", Color.DARK_GRAY);
  86.                 }
  87.             }
  88.         };
  90.         OpenStreetMapImageLayer.prototype.configureLayer = function (dc) {
  91.             if (!this.xhr) {
  92.                 var self = this;
  93.                 var canvas = dc.currentGlContext.canvas;
  94.                 this.xhr = new XMLHttpRequest();
  95.                 this.xhr.open("GET", "https://tiles.maps.eox.at/wmts/1.0.0/WMTSCapabilities.xml", true);
  96.                 this.xhr.onreadystatechange = function () {
  97.                     if (self.xhr.readyState === 4) {
  98.                         if (self.xhr.status === 200) {
  99.                             // Create a layer from the WMTS capabilities.
  100.                             var wmtsCapabilities = new WmtsCapabilities(self.xhr.responseXML);
  101.                             var wmtsLayerCapabilities = wmtsCapabilities.getLayer("osm");
  102.                             var wmtsConfig = WmtsLayer.formLayerConfiguration(wmtsLayerCapabilities);
  103.                             wmtsConfig.title = self.displayName;
  104.                             self.layer = new WmtsLayer(wmtsConfig);
  105.                             // Send an event to request a redraw.
  106.                             var e = document.createEvent('Event');
  107.                             e.initEvent(WorldWind.REDRAW_EVENT_TYPE, true, true);
  108.                             canvas.dispatchEvent(e);
  109.                         } else {
  110.                             Logger.log(Logger.LEVEL_WARNING,
  111.                                 "OSM retrieval failed (" + xhr.statusText + "): " + url);
  112.                         }
  113.                     }
  114.                 };
  116.                 this.xhr.onerror = function () {
  117.                     Logger.log(Logger.LEVEL_WARNING, "OSM retrieval failed: " + url);
  118.                 };
  120.                 this.xhr.ontimeout = function () {
  121.                     Logger.log(Logger.LEVEL_WARNING, "OSM retrieval timed out: " + url);
  122.                 };
  124.                 this.xhr.send(null);
  125.             }
  127.         };
  129.         return OpenStreetMapImageLayer;
  130.     }
  131. );