What are layers ?

Layers are the LuciadRIA view components that process and group the objects of a model to take care of their visualization. A view typically displays multiple layers, which allows you to have objects from multiple data models on screen.

A layer defines:

  • The styling for your objects

  • Whether selection is activated

  • Whether editing is activated

  • Whether labels are visible

  • Whether objects are filtered or not

LuciadRIA comes with a set of pre-defined layer implementations:

  • Layers that visualize (tiled) raster models. See the Visualizing raster data documentation for more information.

  • Layers that visualize vector features. See the Visualizing vector data documentation for more information.

  • Layers that visualize a grid on the map. See the Visualizing a grid documentation for more information.

Different layer types

Associated with each layer is a LayerType. The LayerType is used by LuciadRIA to build up an efficient DOM representation, based on the logical ordering of Layer instances in the map and on the specific LayerType.

The available layer types are:

  • BASE: a base layer is always drawn behind all other data. This type is targeted at raster data such as aerial photography or pre-rendered cartographic imagery.

  • STATIC: a static layer indicates that the model data or the visualization properties are not expected to change frequently.

  • DYNAMIC: a dynamic layer indicates that the model data or visualization properties of the data may change frequently, such as moving flight paths, or frequently edited data.

Common layer properties

All layers have a number of common properties that affect the behavior of the layer and a number of events that can be used to implement application-specific functionality.

For example, setting the visibility property of a layer determines whether the layer is displayed in the map or not.

For the majority of these properties, the layer also fires events when the property value changes. For example the visibilityChanged event will be triggered when the value of the visibility property changes.