emxsys
commented
5 years ago Attempted to use WMTS service. Was FAST, but georeferencing alignment was off E/W ~100m.
/*
* Copyright (c) 2016 Bruce Schubert.
* The MIT License
* http://www.opensource.org/licenses/mit-license
*/
/*global define, WorldWind, $ */
/**
* The USGS TNM Topo Base Map layer.
*
* @returns {UsgsTopoBaseMapLayer}
*/
define([
'jquery',
'worldwind'],
function () {
"use strict";
/**
* Constructs a USGS Topo map layer.
* @constructor
*/
var UsgsTopoBaseMapLayer = function () {
WorldWind.Layer.call(this, "USGS Topo Basemap");
// Web Map Tiling Service information from
var serviceAddress = "https://basemap.nationalmap.gov/arcgis/rest/services/USGSTopo/MapServer/WMTS/1.0.0/WMTSCapabilities.xml";
var layerIdentifier = "USGSTopo";
var self = this;
// Called asynchronously to parse and create the WMTS layer
var createLayer = function (xmlDom) {
// Create a WmtsCapabilities object from the XML DOM
var wmtsCapabilities = new WorldWind.WmtsCapabilities(xmlDom);
// Retrieve a WmtsLayerCapabilities object by the desired layer name
var wmtsLayerCapabilities = wmtsCapabilities.getLayer(layerIdentifier);
// Form a configuration object from the WmtsLayerCapabilities object
var wmtsConfig = WorldWind.WmtsLayer.formLayerConfiguration(wmtsLayerCapabilities);
// Create the WMTS Layer from the configuration object
self.wmtsLayer = new WorldWind.WmtsLayer(wmtsConfig);
};
// Called if an error occurs during WMTS Capabilities document retrieval
var logError = function (jqXhr, text, exception) {
console.log("There was a failure retrieving the capabilities document: " + text + " exception: " + exception);
};
$.get(serviceAddress).done(createLayer).fail(logError);
};
UsgsTopoBaseMapLayer.prototype = Object.create(WorldWind.Layer.prototype);
/**
* Refreshes the data associated with this layer. The behavior of this function varies with the layer
* type. For image layers, it causes the images to be re-retrieved from their origin.
*/
UsgsTopoBaseMapLayer.prototype.refresh = function () {
return this.wmtsLayer.refresh(dc);
};
/**
* Subclass method called to display this layer. Subclasses should implement this method rather than the
* [render]{@link Layer#render} method, which determines enable, pick and active altitude status and does not
* call this doRender method if the layer should not be displayed.
* @param {DrawContext} dc The current draw context.
* @protected
*/
UsgsTopoBaseMapLayer.prototype.doRender = function (dc) {
return this.wmtsLayer.doRender(dc);
};
/**
* Indicates whether this layer is within the current view. Subclasses may override this method and
* when called determine whether the layer contents are visible in the current view frustum. The default
* implementation always returns true.
* @param {DrawContext} dc The current draw context.
* @returns {boolean} true If this layer is within the current view, otherwise false.
* @protected
*/
UsgsTopoBaseMapLayer.prototype.isLayerInView = function (dc) {
return this.wmtsLayer.isLayerInView(dc);
};
return UsgsTopoBaseMapLayer;
});
The USGS Topo WMTS map service from the National Map is much faster than the WMS service and also contains Cache-Control headers.