Writing features in GML format

Question

I would like to use OpenLayers 3 to write GML features.

Here is my code:

proj4.defs("EPSG:25833", "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs");

prjCrs.epsg25832 = ol.proj.get('EPSG:25832');
prjCrs.epsg4326 = 'EPSG:4326';


var features = digitizingVector.getSource().getFeatures();

var format = new ol.format.GML();
var out = format.writeFeatures(features, {
    dataProjection: prjCrs.epsg4326,
    featureProjection: prjCrs.epsg25832
});

However, this always spits out the following error message:

ol.js:357 Uncaught TypeError: Cannot read property 'undefined' of undefined

With ol-debug.js the following error message is returned:

I am using the exact same logic to write features in GeoJSON, KML, GPX, WKT and it works perfecty fine. Is there an issue with GML features in OpenLayers 3?

I am using version 3.19.1 of OpenLayers.

Answer 1

When writing out GML you need to provide some extra config in the constructor of the format, probably featureType, featureNS and srsName.