WFS: Count available feature Types

Question

Some WFS offer a large number of feature types, e.g. a collection of all public datasets from a municipality.

What is the right way to count the number of feature types of a WFS?

My idea was to search the respective XML documents for string that appear once in each feature type block and nowhere else. I searched the GetCapabilties output for and I got 335 results. Then I searched the DescribeFeatureType output for <xsd:complexType and got 339 results. This does not seem the "official" way to do it or maybe I use the wrong search string.

What is the easiest and correct solution here?

Answer 1

I do not really understand this case. It is supposed to get the list of layers by parsing the GetCapabilities document with a real XML parser, but text search with a well selected string can work as well. It is also possible to use some utilities like ogrinfo

ogrinfo WFS:"https://data.wien.gv.at/daten/geo?version=2.0.0&service=WFS&request=GetCapabilities" 

Ogrinfo finds 335 feature Types. But there are really 339 complexType elements in the DescribeFeatureType response. This is one that appears only in DescribeFeatureType:

<xsd:complexType name="PLANUNGASTOGDType">
    <xsd:complexContent>
      <xsd:extension base="gml:AbstractFeatureType">
        <xsd:sequence>
          <xsd:element maxOccurs="1" minOccurs="1" name="OBJECTID" nillable="false" type="xsd:decimal"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="SHAPE" nillable="true" type="gml:GeometryPropertyType"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="NAME" nillable="true" type="xsd:string"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="QUELLE" nillable="true" type="xsd:string"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="FERTIG" nillable="true" type="xsd:string"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="STAND" nillable="true" type="xsd:string"/>
          <xsd:element maxOccurs="1" minOccurs="0" name="SE_ANNO_CAD_DATA" nillable="true" type="xsd:hexBinary"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

I tried GetFeature with this "extra" feature type but it fails maybe due to timeout.

https://data.wien.gv.at/daten/geo?version=2.0.0&service=WFS&request=GetFeature&typeNames=PLANUNGASTOGD

The server still believes that it could do something with that feature type, because a type name like "PLANUNGASTOGDfoo" yields an error message Feature type :PLANUNGASTOGDfoo unknown.

I would say that the WFS server at data.wien.gv.at is now somehow misconfigured. Maybe they have removed 4 feature types from the service but for some reason the server has not removed them from DescribeFeatureType. I would contact the service provider and report the issue. As an answer to your original question, GetCapabilities is the right document for counting the number of feature types.