Visio is a great tool for graphically representing complex systems, processes, and objects. But as consultants, we’ve all received Visio diagrams that were so complex it was hard to make heads or tails of them. (You’ve likely created a few of those, too.)

Luckily, Visio has a feature that can make using complex diagrams much easier. Layers, as the name suggests, let you place the shapes in your drawing on different “levels” and then filter your drawing by choosing to view or not view the different layers in the diagram. I’ll show you how layers work and how to easily go through a diagram and assign the shapes to layers.

Layer basics
In general, all Visio diagrams have two built-in layers: the Connector, and another that represents the shapes (this layer can have different names based on what kind of diagram you have open). Layers for a diagram are viewed, edited, and used in the Layer Properties dialog box, shown in Figure A.

Figure A

This dialog box shows us the names and status of all the layers in the diagram. The properties you can set for each layer are:

  • Visible: If this property is checked, the shapes assigned to this layer can be seen on screen.
  • Print: Here you can specify whether a layer should be printed when the diagram is sent to a printer.
  • Active: The active layer is the one to which new shapes are assigned by default as they’re added to the diagram.
  • Lock: Shapes in a locked layer cannot be selected and therefore cannot be moved or edited.
  • Snap: If snap is not checked, other shapes cannot snap to the shapes on the layer. This can be useful for crowded diagrams in which you don’t want every shape to be “snap-able.”
  • Glue: This property is the same as snap, except it pertains to gluing.
  • Color: Color allows you to set a shape color for every shape on a layer. This can act as a sort of filter in that all the shapes of a certain layer can be made to appear in a particular color, making them easy to find in a diagram.

This dialog box also allows you to add layers using the New button. You can also rename and remove layers. Note that removing a layer also deletes all the shapes assigned to the layer, so remove shapes from the layer before you delete it.

Setting up your diagram for layers
Once you decide to use layers in a diagram, decide how you want to break it down. You might layer a flow chart by the organization responsible for certain parts of a network, for example, or layer an organization chart by skill or geographic location. For this example, you could add layers to a network system diagram (see Figure B). This diagram could be broken down into layers in several ways: equipment type, organization that owns the equipment, or physical location.

Figure B

After you decide how you want to layer your diagram, open the Layer Properties dialog box by clicking on the View | Layer Properties menu item. Adding a new layer to a diagram is as easy as clicking New in the Layer Properties dialog box and giving the layer a name. Figure C shows an example of how the dialog box might look after adding layers for the network system sample diagram. I’ve created layers for location and equipment type.

Figure C

Next, you’ll assign the shapes in your diagram to their layers. The easiest way to do this is to show the Format Shape toolbar by clicking Tools | Customize to bring up the Customize dialog box. Select the Toolbars tab and then check the box next to Format Shape. This toolbar has a drop-down control, which allows you to assign the selected shape or shapes to one of the layers in the diagram.

To do this, select a shape from your Visio diagram and then pick a layer from the drop-down list. To select more than one shape, hold down the [Shift] key while you’re selecting. To assign a shape to more than one layer, pick {Multiple Layers} from the drop-down list, and Visio will bring up the Layer dialog box, shown in Figure D.

Figure D

The highlighted entries in the list indicate the layers to which the shape belongs. To add the shape to another layer, hold down the [Ctrl] key and select another shape from the list. Click OK when you’re finished.

Filtering your diagram
After you have your shapes assigned to layers, you can start filtering the diagram. Bring up the Layer Properties dialog box by clicking View | Layer Properties. Then, uncheck the Visible property for all the layers you don’t want to see (see Figure E).

Figure E

Click OK to see the diagram filtered down to show just the selected layers. Figure F shows the resulting filtered diagram.

Figure F

As with any newly found feature, create a test file or make a copy of an existing Visio file you’re working on and experiment with layers to see how you might make best use of them in your work. With any application, the best way to get to know a new feature is to try it out.