Operational layers in the Flex API
Operational layers focus primarily on dynamic data. In other words, data that can change more frequently than that of a cached basemap. Many times these layers encapsulate related content, such as earthquake, weather, and traffic data. Operational layers can be differentiated a couple of different ways, either as server-side image results or, client-side graphics.
Server-side image results
ArcGIS for Server hosts both cached and dynamic data. The operational layers, or dynamic layers, inherit directly from the DynamicMapServiceLayer class, which in turn, extends the Layer class. These types are:
Client-side graphics allows information to be displayed more efficiently on the client machine. This is typically done in use cases that involve graphics as user input for markup or a task, or the graphics can be drawn as an output response from a task. The client-side graphics layer types include:
- GraphicsLayer, for more information regarding working with graphics and the GraphicsLayer, see Using Graphics
- FeatureLayer, this layer extends GraphicsLayer. For more information regarding working with feature layers, see Feature Layer
- CSVLayer, this layer extends FeatureLayer. For more information regarding working with the CSVLayer, see CSVLayer
- GeoRSSLayer, this layer extends directly from the Layer class and is used to create a layer based on GeoRSS. GeoRSS is a way to add geographic information to an RSS feed
- KMLLayer, this layer extends directly from the Layer class and is used to create a layer based on publicly accessible KML or KMZ files. For more information regarding working with KML data, please see KML support in ArcGIS Server.
In addition to the layer types listed above, there is an additional MapImageLayer type. This directly inherits off of Layer and is used to add georeferenced images to the map. It is used to work with dynamically generated Map Image objects. A MapImage is accessed a couple of different ways:
- GroundOverlays - come back as part of KML. Every ground overlay is treated as a map image where MapImage.source is the URL to the image.
- Geoprocessing operations - The export operation on ArcGISDynamicMapServiceLayer returns a MapImage in addition to GeoProcessor.getResultImage.