Selecting WMS Layers

Once you've connected to the Web Map Service (WMS) you specified:



and have set the minimum raster cell size in the Raster Resolution panel of the Open Content dialog box, you can add WMS group layers and sublayers. These layers appear in the Add WMS Layers panel which displays the WMS service layer for the service to which you are connected.

A WMS service layer is made up of three types of layers that are arranged hierarchically. At the top is the WMS service layer, which holds all the other WMS layer types. There is only one service layer per WMS service. The next level consists of WMS group layers, whose only function is to organize WMS sublayers into related groups. There can be any number of WMS group layers and nested groups within groups. WMS group layers do not hold any map features—it is the third group, WMS sublayers, that actually contains the map features.

At the left of the Add WMS Layers panel you'll see a treeview of the service layer and all its group layers and sublayers. When you select a sublayer, the lower half of the dialog box displays information the data provider supplied that describes the content available at the service. Note that this information will vary from supplier to supplier.

To select a sublayer for inclusion in the map

Select the sublayer in the treeview at the left and click the right arrow button.

To select all the sublayers of a layer for inclusion in the map

Select the layer in the treeview at the left and click the right arrow button. The sublayers beneath the layer are added.

To select more than one sublayer for inclusion in the map simultaneously

Select the layer in the treeview at the left and then hold down the CTRL key to select any other sublayers. Once you've selected the sublayers you want, click the right arrow button. The selected sublayers are added.

To move the display position of a layer

Select the layer in the list at the right and click one of the arrow keys to move the layer up or down. The appropriate arrow disables if the selected layer is at the top or the bottom of the list.

To remove a layer from the list of layers you have chosen to add to the current map

Select the layer and click the Remove Layer button at the right of the dialog box.

Once you've performed any of the above actions and want your changes to appear in the map, click Next to display the panel to exercise the disk caching options available for the data. To back out of the dialog box and not add any layers, click Cancel.

Layer names in the Contents window

If you've selected more than one sublayer to add to the map, the collection will be represented as one element in the Contents window with the WMS Service Name; on the other hand if you've selected only one sublayer, it will appear in the Contents window with its actual name. All Contents window actions will apply to the collection or the individual layer respectively; for example, toggling the checkbox will toggle the visibility of all members of a collection of sublayers as one or just the individual layer. You may find that it is more appropriate to your workflow to add individual sublayers.