Indicates the identifier specific to a layer as a function of its position. The position value is the position of the layer in the list (0 for the first layer in the list, 1 for the next layer and so on). This command returns the identifier of the corresponding layer or NONE if there is no layer at the specified position. Note that each layer identifier is unique in any one project. When you execute a George script on a project containing several layers, the first thing you should do is to determine the identifier of each layer.