Layer Functions and Commands

Overlay files can be composed of a single layer, or divided into up to 32 different layers.

• When a single layer is used, the complete overlay is always displayed (this includes all lines, text and icons).

• When multiple layers are defined, any combination of layers can be displayed at runtime.

For example, there may be a main layer called coastlines that is always displayed and other layers such as roads, rivers, power plants, that can be turned on or off individually. Each layer can contain lines, text and icons.

When defining layers in an overlay file, all entries in the file that occur after the initial layer command are applied to that layer. This continues sequentially through the file until the file ends, or another layer command is encountered.

Layer Definition Commands

Command	Description
LAYER name	Defines a layer called name. All commands following in the overlay file (until another LAYER command is encountered) are applied to this layer. You can enable this layer at run time by selecting its name in the display options menu.
LAYER_COLOR name color	All lines defined in the layer called name are drawn in the color. The color must be overlay1, overlay2, or overlay3. The colors are defined in color_setup.