Now that you've seen what are the basics of manipulating layers, you will more easily understand why layers are such a powerful tool when you are building and maintaining diagrams with Dia.

Understanding what layers are for can dramatically improve the quality and the visual effect your diagrams will produce.

For instance, imagine you are building a diagram with lots of objects in it, like an Electrical or UML diagram, if you drop all of your objects in the same layer, meaning the background, after a while you will get a huge unmanageable draft you won't be able to do anything with it. It will be a pain to change anything in it, you will waste time trying to remember what object is connected to that object which seems to take all the space in the middle of the mixed up objects you already put there.

Since Dia is a Structured Diagram Builder, all the diagrams you will build with it will be naturally structured and broken down to many little pieces. Using a layered approach better manages lots of pieces with more ease and efficiency than you could do with a single monolithic block of objects.

	By definition, a diagram should be structured. So breaking it down into several logical parts should be an easy process. That's where layers become a very useful and important tool for the management of the content of diagrams. They allow you to isolate each of these parts in separated slides, so it becomes a real pleasure to manipulate them in any way you like.

The Eye Icon to the left of the layer name is what make layers so useful. It allows you to show or hide the corresponding layer. Meaning if for any reason you decided to not show a particular layer, simply click on the Eye Icon and the layer and everything it contains will disappear from the Canvas. If you hold down the Shift key and click Eye Icon you can hide all the other layers except for the current layer, and if you click again while still holding the Shift key all Layers will be shown again.

Viewing only certain layers is really useful when you want manipulate a small part of your diagram without affecting the rest. Some users create separate layers to hold all their text objects and use different layers to hold translations into other languages. You can also work that way if you want to print your diagram on different pages or testing different settings which can affect the layout of that part. Again, feel free to experiment with layers, if set up properly they can make your diagram look much better.

	In Dia, Layers creation and manipulation are as common as drawing or selecting objects in the diagram. You must get your hands on them, because you will probably have to use them anytime you will want to create a new diagram.