### Layer Explorer

The Layer Explorer area of the Main Window shows all layers selected by the menu Project > Add Layer.... To draw one or more layer at the Map Display, check its box and reach (pincel).
The Spatial Reference System of the Map Display will be the first valid SRID among the layers checked an its is showed at the status bar. It is also possible to set the Map Display SRID by right-clicking over the Map Display area as explained here. To find out the layer-SRID, right-click over a layer name and choose Properties.... More actions over layers will be explained here and via Layer and Map Display Menus.
NOTE: Each layer can be in one of the 4 status:

- box-checked

- selected

- box-checked and selected

- none

Some actions at the Layer Explorer and at the Map Display depends on the layer status. Keep this in mind from now on and see how to select one or more layers at the Layer Explorer below.

#### Layer Explorer - Selecting one or more layers

Clicking over a layer name makes it selected and the actions available from the context menu can be executed.
Right-clicking over a layer name makes it selected and shows a context menu of actions that can be executed over a layer. Those actions are also accessible through the Layer Menu.
Shift+clicking allows to select a consecutive set of layers by clicking over the first and the last layer names in the tree. A highlighted area appear in the tree and r ight-clicking over this area shows a context menu of actions that can be executed over more than one layer, for example Remove Layer(s).
Ctrl+clicking allows to select a non-consecutive set of layer by clicking over layer names in the tree. All layer names will became highlighted and right-clicking over one of them shows a context menu of actions that can be executed over all selected layer.
Note that the layer does not need to have its box-checked to execute some actions. For example, to execute Remove Layer, Show Table or Classification... it is enough to select a layer. All layer actions can also be accessed via Layer Menu.