Custom DynamicLayer

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This sample demonstrates how to create a custom dynamic layer with a WMS service. The WMS service is accessed from geobretagne server.

This sample uses a WMS service for demonstration purposes only. The ArcGIS API for JavaScript has a WMSLayer type that should be used for working with data in WMS. See the WMSLayer sample for more details.

To create a custom dynamic layer, you must call createSubclass() on BaseDynamicLayer. We'll call the custom dynamic layer CustomWMSLayer and give it two public properties that can be watched for changes. They are be used to generate a URL to request an image from a WMS server. The properties are:

  • mapUrl - specifies the URL to a WMS service
  • mapParameters - specifies query parameters that will be used when fetching image from the server
const CustomWMSLayer = BaseDynamicLayer.createSubclass({
  properties: {
    mapUrl: null,
    mapParameters: null
  // ...

The CustomWMSLayer implements the getImageUrl() method to generate the URL to an image for a given extent, width, and height. This method manipulates values of the mapUrl and mapParameters properties to generate the URL to an image which will be displayed in the view.

// Override getImageUrl() method to generate URL
// to an image for a given extent, width and height.
getImageUrl: function (extent, width, height) {
  const urlVariables = this._prepareQuery(this.mapParameters, extent, width, height);
  const queryString = this._joinUrlVariables(urlVariables);
  return this.mapUrl + "?" + queryString;