On the website <https://www.bezreg-koeln.nrw.de/brk_internet/geobasis/webdienste/anleitung_wfs.pdf> is shown how to use filters in OGC WFS. There is also an example request:

```
https://www.wfs.nrw.de/geobasis/wfs_nw_dvg?VERSION=2.0.0&SERVICE=WFS&REQUEST=GetFeature&TYPENAMES=nw_dvg1_gem&FILTER=<Filter><PropertyIsEqualTo><ValueReference>GN</ValueReference><Literal>Kerpen</Literal></PropertyIsEqualTo></Filter>

```

Well, I have got another WFS from the same domain and there the filter does not work.

WFS capabilities:

```
https://www.wfs.nrw.de/geobasis/wfs_nw_alkis_aaa-modell-basiert?REQUEST=GetCapabilities&SERVICE=WFS

```

WFS Request test with filter (adopted from the upper example but of course by using a layer and a filter attribute from the new WFS):

```
https://www.wfs.nrw.de/geobasis/wfs_nw_alkis_aaa-modell-basiert?VERSION=2.0.0&SERVICE=WFS&REQUEST=GetFeature&TYPENAMES=AX_Flurstueck&FILTER=<Filter><PropertyIsEqualTo><ValueReference>gemarkung</ValueReference><Literal>Dortmund</Literal></PropertyIsEqualTo></Filter>

```

When I try to load that WFS request I get the following response in my browser:

```
<ExceptionReport xmlns="http://www.opengis.net/ows/1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.0.0" xsi:schemaLocation="http://www.opengis.net/ows/1.1 http://www.wfs.nrw.de/aaa-suite/schema/ogc/ows/1.1.0/owsExceptionReport.xsd">
    <Exception exceptionCode="InvalidParameterValue" locator="FILTER">
        <ExceptionText>
            Request rejected due to errors. InternalExceptionCode: iiOperationParsingFailed. Reason:
            <![CDATA[ Element 'Filter' not in expected namespace (http://www.opengis.net/fes/2.0) ]]>
        </ExceptionText>
    </Exception>
</ExceptionReport>

```

Why does the filter options work on the one but not on the other WFS?

And how is it possible to add filter options instead?

In the description of the WFS it is said that it is especially built to serve filtered data.