WFS to JSON vector layer error when specifying srsname in query string, no features when specifying value of DefaultCRS in OpenLayers 4?

Question

I'm following the example from the official OL site for WFS, but I cannot get it to work with a different Feature Server when I add srsname= to the query string as specified in the example:

GET http://fbinter.stadt-berlin.de/fb/wfs/geometry/senstadt/re_spielplatzbestand/?service=WFS&version=2.0.0&request=GetFeature&typenames=fis:re_spielplatzbestand&outputFormat=application/json&srsname=EPSG:3857&bbox=1451195.2005082138,6878797.486467866,1529696.0285570899,6909372.297781937,EPSG:3857

Status Code: 400 Bad Request
Response Body:
<?xml version="1.0" encoding="UTF-8"?>
<ows:ExceptionReport xmlns:ows="http://www.opengis.net/ows/1.1" version="2.0.0">
  <ows:Exception exceptionCode="InvalidParameterValue" locator="service">
    <ows:ExceptionText>parameter SRSNAME invalid</ows:ExceptionText>
  </ows:Exception>
</ows:ExceptionReport>

Leaving srsname out produces a response with 0 features:

GET http://fbinter.stadt-berlin.de/fb/wfs/geometry/senstadt/re_spielplatzbestand/?service=WFS&version=2.0.0&request=GetFeature&typenames=fis:re_spielplatzbestand&outputFormat=application/json&bbox=1451195.2005082138,6878797.486467866,1529696.0285570899,6909372.297781937
{
  "type":"FeatureCollection",
  "totalFeatures":0,
  "features":[],
  "crs":{"type":"name","properties":{"name":"EPSG:25833"}}
}

I also tried with srsname=EPSG:25833 and appending .EPSG:25833 for the respective bits in url: function(extent) since it is the default projection that appears in GetCapabilities, but got the same result.

https://jsfiddle.net/bapms31j

Without the bbox filter, the URL for GetFeatures returns 1809 features, so it's definitely not a problem from the Feature Service. The same WFS vector layer works flawlessly in QGIS:

Also tried changing version to 1.0.0 and 1.1.0 without success.

Answer 1

It seems to be a problem of projections:

The WFS allows only requests usings SRID 25833. A working example, including the bounding box parameter, is http://fbinter.stadt-berlin.de/fb/wfs/geometry/senstadt/re_spielplatzbestand/?service=WFS&version=2.0.0&request=GetFeature&typenames=fis:re_spielplatzbestand&outputFormat=application/json&srsname=EPSG:25833&bbox=392215,5818350,393129,5817949,EPSG:25833

Your OpenLayers map uses SRID 3857 as default. So, when including the current map extent using extent.join(',');, OpenLayers sends the bounding box in SRID:3857 coordinates whereas the WFS expects coordinates in SRID 25833.

Solution:

1. Transform your bounding box parameters from SRID 3857 to SRID 25833.

2. Transform the received features from SRID 25833 to SRID 3857 before viewing on the map.