Query WFS features
The query of a Web Feature Service (WFS) enables access to the provided vector data with factual information (attribute data) and its further use.
The transferred WFS data can, for example, be stored in a depot for further processing in the switchboard or visualized in a layer.
Query WFS Anchor
In the first step, add the URL of the WFS in the function Import WFS.
Features from WFS queries the WFS and returns the features provided by the WFS as output.
You can then store these in a layer using Store in Layer, for example.
Query WFS special case Anchor
For the import of services that are provided on older servers and contain more than 1000 features, we recommend performing the import tile by tile. Especially for versions younger than WFS 2.0.0.
To do this, you must extend the switchboard described above as follows:
The service is imported with Import WFS and its spatial extent is queried via Bounding Box. The function Bounding Box as Polygon is now used to convert the bounding box created into a Feature. This is necessary because the following function Box Grid expects the data type Feature as input in order to be able to create rectangular tiles.
Depending on the size of the WFS, edge lengths of 500 m or 1000 m have proven to be efficient. You can of course adjust the edge length of the grid individually according to the size of the respective WFS.
Features from WFS now retrieves the 2D objects of the WFS service. As this should only take place within the spatial extent of the WFS, the second input parameter of Features from WFS expects the previously created bounding box.
If more than one tile is to be calculated, you can use the Bounding Box function. This function returns a 2D bounding box for each of the previously calculated tiles. A feature query is now carried out in each tile. In some cases, features now occur several times because their area is mapped in several tiles. You can filter and remove these duplicates with Unique Objects.
The finished data can then be stored in a layer using Store in Layer.
You can download the sample switchboard here:
