Adding layers to the map

The Map.addLayer() method takes an instance of a layer (ArcGISDynamicMapServiceLayer or ArcGISTiledMapServiceLayer in our examples) as the first parameter, and an optional index that specifies where it should be placed. If you don't specify an index, the layer will be placed on top of all the other layers in the map, which is often what you want so that you can be sure it is visible.

In the following code example we create a new instance of ArcGISDynamicMapServiceLayer. We then call Map.addLayer(), passing in the new instance of the layer. The layers in the service will now be visible on the map:

var operationalLayer = new ArcGISDynamicMapServiceLayer("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Population_World/MapServer"); 
map.addLayer(operationalLayer); 

If you want to add more than one layer to the map in one go, you can use Map.addLayers(), which accepts an array of layer objects.

As well as being able to add layers to a map you can also remove them by using Map.removeLayer(layer) or Map.removeAllLayers().