Map layer hierarchy

As you import different data source types a layer hierarchy is built up consisting of layers and sublayers. Data sources of the same type are grouped as sublayers of a parent layer.

In the following figure, the ESRI/Shape (see Shapefile format) and GeoTIFF (see GeoTIFF format) files are grouped as sublayers under their parent layers. The last layer in the hierarchy becomes the front layer in the Map View pane. For example, the Labels layer is displayed in front of the GeoTIFF layer in the Map View pane.

You can rename layers and sublayers to make the name more meaningful, (see Renaming a map layer). For example, San Francisco Streets would be more meaningful than SF_Streets.shp.

You can also set up your own layer hierarchy by creating new layers and sublayers, (see Creating a map layer hierarchy). You can then fill them with one or more of the data sources you have already imported.

The following figure shows an example of a new parent layer called Top Layer into which the SF_Streets.shp file has been placed.

Map layers can also be hidden from the layer tree, (see Hiding and showing a map layer in the tree). For example, in a case where users can add more map layers to an application that has a fixed background map, the application developer may want to ensure that the user cannot alter or remove this background map. The solution to this problem is to hide those layers from the tree so that they cannot be modified.

You also have the possibility to move layers to different positions in the hierarchy and to split layers or create filters on layers that contain metadata (see Splitting or filtering a map layer). You can send layers to the front (top) or back (bottom) of the hierarchy, or change the position of a layer within the hierarchy.

The filtering mechanism allows you to create a layer that displays only the objects that match a filter. You can also split a layer by grouping together the objects that match the same value for selected metadata. In both cases, the split/filtered layers are added to the map layer hierarchy.

The following figure shows an example of an ESRI/Shape file displayed according to a CONTINENT filter.

A pop-up menu is available in the Map Layers pane that allows you to carry out most of the operations available in the Map Layers pane. For more information, see Managing map layers and Split or filtered map layers.