ArcGIS Explorer - Legend Window

Legend Window

If you want to see the legend information for a layer, you can select the layer in the Contents window and click the Show Legend button on the layer’s Tools tab or in its context menu. Show Legend opens the Legend window with the layer selected and its legend displayed in the window:

If the Legend window was already open, it becomes the active window and its combo box switches to the layer that was selected when the Show Legend button was clicked.

Each sub-layer for the layer is displayed expanded by default with its various symbols beneath. The symbols and their labels are basically a picture and non-interactive. The only elements in the legend that are interactive are the arrows next to the sub-layer’s name. You can click the arrow to collapse that sub-layer’s legend information. If you hold down the Ctrl key when you click the arrow, it has the effect of expanding or contracting all of the sub-layers.

The combo box at the top of the window displays the list of layers in the map alphabetically. You can switch the layer and it displays that layer’s legend in the window:

The following are examples of legends for the different types of layers that you see in ArcGIS Explorer:

Feature layers: these are simple single symbol legends and this is reflected in the legend that you see. The following are two examples:
Raster Layers: Raster layers will have legends that depict RGB, color ranges, grayscale, etc. The following is an example of a legend for a raster layer:
ArcGIS Layers and Layer Packages: these items represent ArcMap documents that have been published as either dynamic or cached map services. In either case, their contents are composed of sub-layers that essentially mirror the map document’s contents in ArcMap. As such, these sub-layers might have single symbols, unique value renderers, be organized into group layers, etc. Note that when you add a map server layer to ArcGIS Explorer you can choose which layers are visible by changing the Layer Properties dialog's Sub-layers sheet. The legend for a map server layer will only display those layers that have been checked as visible.

The following are examples of the type of legends you might see from a map server (these are simple examples with no group layers):
- ArcGIS Globe Service Layers: a globe service layer doesn’t contain any sublayers and its legend reflects the legend of the layer that was published as part of publishing a globe document. So, it can be a single symbol, unique value renderer, raster renderer, etc. The following is an example of a globe service layer:
- IMS Layers: IMS layers are similar to map server layers in that they have a number of sublayers that can be single or multiple symbols, raster, etc. Also similar to map server layers, when you add an IMS service to ArcGIS Explorer, you can choose which layers to be visible (this can be changed in the property page later also). Only those layers that are visible will be displayed in the Legend window. The following is an example of the legend for an IMS service from the Geography Network:
- WMS Layers: WMS layers are unique in that unlike the other layer types described above, the legend information for a sublayer is drawn by the server and returned to the client (ArcGIS Explorer in this case) as an image. So for WMS layers, under each sublayer, the image returned from the server is displayed. Also, WMS layers can contain a very large number of sublayers that can be nested several hierarchies deep.
  When you add a WMS service to ArcGIS Explorer, you can choose which sublayers to include. The set of included sublayers is modifiable in the layer’s Properties page on the Sub-layers sheet. The legend only displays the sub-layers that you set to be visible.

KML and KMZ files

KML has a number of sub elements (i.e. KML Nodes) arranged in an arbitrary hierarchy. You'll find that KML and KMZ files you add to the map will display in the Contents window. These are not included in the legend because these nodes have more functionality associated with them than do the items of legend information for a layer. For example, you can navigate to a node, display its popup window, use it as input to a result, etc.

The KML node hierarchy for KML will be displayed in-line in the Contents window with each node establishing context when it’s selecte. Additionally, sub-nodes can be turned on or off, etc, etc. The design for displaying and interacting with KML contents will be detailed in another design document.