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:

enter image description here

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.

  • What is the error message when using ol-debug.js ?
    – bartvde
    Jan 10, 2017 at 10:45
  • Thank you, I have updated my question accordingly. I also mentioned that I am using version 3.19.1. Jan 10, 2017 at 11:02

1 Answer 1


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

  • That worked! All of the above had to be entered: featureNS, featureType, srsName. Jan 11, 2017 at 9:09
  • What surprise me is that featureNS, featureType and srsName are optional but there is an error in JS if there are not defined. Sep 3, 2020 at 13:02

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