diff --git a/examples/layer/map.layer.idw.html b/examples/layer/map.layer.idw.html
index 0f6cf207..d30e4d3c 100644
--- a/examples/layer/map.layer.idw.html
+++ b/examples/layer/map.layer.idw.html
@@ -87,11 +87,28 @@ <h1>ol-ext: IDW layer</h1>
 	<div id="map"></div>
 	<div class="options">
     Click on the map to add a new measure.
-    <br/> Value:
-    <input id="value" type="number" value="50" min="0" max="100" />
-    <label><input id="random" type="checkbox" checked="checked" /> random</label>
-    <button onclick="idw.getSource().clear()">clear</button>
-    <button onclick="$('body').toggleClass('fullscreen'); map.updateSize()">FullScreen</button>
+    <ul>
+      <li>
+        Value:
+        <input id="value" type="number" value="50" min="0" max="100" />
+        <label><input id="random" type="checkbox" checked="checked" /> random</label>
+      </li>
+      <li>
+        Scale: <select onchange="idw.setScale(this.value)">
+          <option valule="1">1</option>
+          <option valule="2">2</option>
+          <option valule="4" selected>4</option>
+          <option valule="8">8</option>
+        </select>
+      </li>
+      <li>
+        Max distance: <input type="range" step="100000" min="0" max="4000000" value="0" onchange="idw.setMaxD(this.value)">
+      </li>
+      <li style="padding-top: 1em; float: right;">
+        <button onclick="idw.getSource().clear()">clear</button>
+        <button onclick="$('body').toggleClass('fullscreen'); map.updateSize()">FullScreen</button>
+      </li>
+    </ul>
 	</div>
 	
   <script type="text/javascript">
diff --git a/src/source/IDW.js b/src/source/IDW.js
index 96cb28d3..e64edae8 100644
--- a/src/source/IDW.js
+++ b/src/source/IDW.js
@@ -55,6 +55,20 @@ var ol_source_IDW = class olsourceIDW extends ol_source_ImageCanvas {
     this.set('maxD', parseFloat(options.maxD) || 0) 
     this._weight = typeof (options.weight) === 'function' ? options.weight : function (f) { return f.get(options.weight || 'weight'); };
   }
+  /** Set IDW scale
+   * @param {number} scale
+   */
+  setScale(scale) {
+    this.set('scale', parseFloat(scale) || 4);
+    this.changed();
+  }
+  /** Set IDW max distance
+   * @param {number} [dist] max distance in proj units
+   */
+  setMaxD(dist) {
+    this.set('maxD', parseFloat(dist) || 0);
+    this.changed();
+  }
   /** Get the source
    */
   getSource() {