Maps consist of several elements: terrain, doodads, units, locations and the fog of war. Each of these elements has been separated into a distinct layer.
While working in the Terrain layer, your cursor will be the diamond-shaped terrain brush. You can use this brush to paint terrain. When placing terrain, you can click multiple times in the same location to cycle through artwork variations. For more information on placing terrain, see the Changing the Terrain section.
Trees, craters, ramps and other unique terrain features are Doodads. While working in the Doodad layer, you can place, select and delete doodads. Use the Doodad Palette to choose a doodad brush. For more information, see the Placing Doodads section.
Buildings, units and resources are all placed in the Unit layer. While working in the Unit layer, you can place, select, delete and modify properties for units. For more information about placing units, see the Placing Units section.
Locations are rectangular regions used with Triggers. This is an advanced feature that is not required to make a map. Locations are only visible when the Location layer is the current layer. For more information about creating Locations, see the Creating Locations sections.
In Starcraft, the area that is no longer in the vision of any of your units or buildings is called the “Fog of War.” While working in the Fog of War layer, you can mark areas of fog as fully or partially obscured. The Fog of War layer can be set separately for every player, or can be set for all players in a scenario. The fog is only visible when the Fog of War layer is the current layer. For more information about modifying the Fog of War, see the Uncovering the Map section.
Layers can be selected using the Layer menu or by right-clicking in the main window and using Layer in the pop-up menu.
Note: You may only modify and select elements while in their current layer. For instance, Doodads cannot be selected when you are in the Unit layer.