Currently there is no OGC standard service to generate KML documents. Since KML are mainly features, a WFS could be used as an option. Nevertheless since KML is intended for visualization (as stated in the OGC References framework), a WMS that generates KML is also a logical alternative. The later was the route followed by GeoViQua to profit the already existent WMS. KML‐Q files are integrated in the GeoViQua general architecture as a WMS‐Q service able to generate KML as output format. This way the same connector developed in the DAB‐Q to integrate the WMS‐Q is used to integrate KML in the discovery phase. In the visualization phase, the KML is served as a result of a GetMap operation to the WMS.
The project speculated with the possibility of creating a KML‐Q extension that required a modified KML client. To favour interoperability, GeoViQua finally decided to apply a set of KML conventions to express quality by colouring changing or by changing the height of the objects. This way KML‐Q instances, describing quality variables in KML format, can be integrated into the Geoportal creating links to the main URL of the service. These links can be included in the same way than WMS‐Q is done. These links will generate a query to a KML client such as Google Earth or World Wind that need to be installed in the client computer in the form of an application or a plug‐in. For the GeoViQua Geoportal mirror, an icon similar to the Google Earth has been chosen to show the kind of source these links relates to.
More information in:
KML-Q, KML, code. Fraunhofer(FRAUN)