Managing group layers
Release 9.3 Last modified October 5, 2010	Print all topics in : "Working with layers"

About group layers

Note: This topic was updated for 9.3.1.

A group layer contains other layers. Group layers help organize related kinds of layers in a map and can be used to define advanced drawing order options. For example, suppose you have two layers on a map representing railroads and highways. You might choose to group these layers together and name the resulting layer Transportation Networks. If you need to, you can even create groups of group layers (nested group layers).

A group layer behaves similarly to other layers in the table of contents. Turning off the visibility of a group layer turns off the visibility of all its component layers. A group layer's properties override any conflicting properties of its constituent layers. For example, a visibility scale range set on a layer will be overridden by a visibility scale range set on the group layer.

You can change the properties of any of the layers inside a group layer. You can change the drawing order of the layers in the group layer and add and remove layers as needed. You can also choose to use symbol level drawing for all the symbols that the layers inside the group layer uses by opening a group layer's properties and clicking the Symbol Levels button.

Dragging and dropping layers into group layers

You can drag and drop layers to add them to group layers. When the insertion bar is at the end of a group layer, a small indicator at the left end of the bar appears:



When you see the indicator on the insertion bar, you can move the mouse pointer either left or right to indicate where you want the layers dropped. The insertion bar will extend to the left as you drag the mouse pointer to the left, and the indicator at the end of the bar reflects where the layers will be dropped in the hierarchy.

• Drag layers up so the insertion bar is under the expanded group layer. If you want to drop the layers into the group layer, position the insertion bar so it's indented to the right.
  
• If you want to drop the layers after the group layer (instead of into it), move the mouse pointer to the left. The insertion bar will extend to the left to show that the layers will be dropped after the group layer.
  

Similarly, you can drag layers into a new, empty group layer. When you drag layers under an empty group layer, you can choose whether the layers get dropped into the group layer or after it. When the insertion bar is under the new group layer, move the mouse pointer either left or right to make the choice.

Group and composite layers in dialog box lists

Lists of layers in dialog boxes show you which layers belong to group layers or other composite layers such as ArcIMS image services. These lists match the way the layers are organized in the table of contents. Each layer is listed with its layer icon from ArcCatalog so you can easily see what type of data each layer contains.
You can expand and contract the list to quickly access the layer you want to use. If the layer names are very long, a horizontal scale bar at the bottom of the drop-down list lets you scroll through the listing sideways.




In addition, the table of contents Selection tab and the Set Selectable Layers dialog box let you choose which feature layers will be selectable by interactive tools. The way that layers are listed on the Selection tab and the Set Selectable Layers dialog box also shows you how the layers are organized into groups. Feature-based sublayers of ArcIMS image services in which features can be selected are also grouped under the service to which they belong.

How to manage group layers

Creating a group layer

1. In the table of contents, right-click the data frame in which you want to create a group layer and click New Group Layer.
   
A new group layer appears in the table of contents.

Tips

You can also create your group layer in the Catalog tree of ArcCatalog. Right-click the folder in which you want to store the new layer, point to New, then click Group Layer and type a name for it. You can also create a group layer by selecting several map layers in the table of contents, right-clicking the selected layers, and clicking Group. To group them this way in ArcCatalog, select the data sources in the Catalog tree, right-click one of them, and click Create Layer.

Adding layers to a group layer

1. Right-click the group layer in the table of contents and click Properties.
   
2. Click the Group tab and click Add.
   
3. Click the Look in drop-down arrow and navigate to the data source you want to add to the group.
   


4. Click the data source.
   
5. Click Add.
   

Tips

If the layer you want to add to a group is already in the map, you can drag and drop it in the group layer. If you already have more than one layer in the map, select all of them and drag and drop them into the group layer. To select more than one layer, press the Ctrl key when you click each additional layer. The drawing order for the group layer is the order in which the layers are listed in the group. If you are dragging data into ArcMap from ArcCatalog, you can hover over any data frame or group layer expansion control to expand or collapse it, allowing you to drop the data exactly where it belongs. To add layers to a group layer in ArcCatalog, right-click a group layer in the Catalog tree, click Properties, then click the Group tab and add the layers you want.

Changing the layer order in a group layer

1. Double-click the group layer in the table of contents to display its properties.
   
2. Click the Group tab.
   
3. Click the layer you want to move.
   
4. Click the appropriate arrow button to move the layer up or down.
   
5. Click OK.
   

Tips

You can also drag and drop a layer inside a group layer to a different position within the group layer. You can select and drag more than one layer within a group layer to change the drawing order by pressing the Ctrl key when you click each additional layer.

Creating nested group layers (within other group layers)

There are several ways to create group layers within other group layers.

1. Drag and drop any group layer into any other group layer.
   
2. Or select multiple layers in the table of contents (including group layers), right-click, and click Group. You can also select layers that are already in a group layer, right-click, then click Group to create a nested group layer.
   
3. Or right-click a group layer, click New Group Layer, then drag layers to the new empty group layer.
   

Displaying the properties of a layer in a group layer

1. Double-click the group layer in the table of contents to display its properties.
   
2. Click the Group tab.
   
3. Click the layer whose properties you want to display.
   
4. Click Properties.
   
You can now modify the layer's properties.

5. Click OK.
   

Tips

You can also double-click the layer name of any layer inside the group layer to display its properties. You can set the transparency of group layers with either the Effects toolbar or the Display tab of the Group Layer Properties dialog box. Leave the transparency of a group layer at 0 percent if you want the transparency setting of each layer the group contains to be used when it is drawn. Setting the transparency of a group layer to be greater than 0 percent overrides the transparency setting of each layer in the group. All the layers will be drawn with the transparency you choose, irrespective of their individual transparency settings. The transparency property of each layer in a group isn't modified by setting the transparency at the group layer; it is just ignored. In this way, you can switch between setting transparency at the group layer level or using the transparency settings of the layers in the group. Learn more about making your layers transparent

Removing a layer from a group layer

1. Double-click the group layer in the table of contents to display its properties.
   
2. Click the Group tab.
   
3. Click the layer you want to remove and click Remove.
   
4. Click OK.
   

Tips

You can also right-click the layer name of any layer inside the group layer to show its context menu and click Remove to remove a layer from a group layer. To remove several layers from a group layer, hold down the Shift key or the Ctrl key to select more than one layer in the group. You can drag a layer out of a group layer and drop it anywhere else in the table of contents.

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