I have a problem with OL3 and it's ol.interaction.Modify Event. Whenever I modify a feature, just one, it returns all features inside the layer. Currently I have 77 features (polygons) and I can modify them with the modify interaction. Inside the callback function it returns the event with the feature member array and this seems to be buggy:

modify.on('modifyend', function(e) {

    console.log('=== Modify end ===');
    var modifiedFeature = e.features.item(0);

    //Why do I get 77 modified features if I have only touched one?
    // e.features size is = 77

Do you know a working way to get the one modified feature?

1 Answer 1


I guess you pass all the features to the modify interaction. That is why it returns all of them (If you dont provide your code I can only guess). You can always use a select interaction and then pass the selected feature to modify interction. For your case you may iterate through your features and check for the revision, each time a feature is modified, its version number will be incremented.

So do something like this

var modifiedFeatures;
modify.on('modifyend', function(e) {
    var features = e.features.getArray();
    for (var i = 0; i < features.length; i++) {
        var rev = features[i].getRevision();
        if (rev > 1) {
            console.log("feature with revision:" + rev + " has been modified");

check this fiddle.

  • Hi Pavlos, yes your are right, I pass all features and so it returns all features. Thanks very much for the hint with the Revision number. This resolved my problem.
    – Brain
    Commented Jan 7, 2016 at 8:46
  • glad to help amigo!!
    – pavlos
    Commented Jan 7, 2016 at 9:13
  • It's becoming horrible when you have to save the features. The revision indexes increase each time, then you cannot count on it. Too bad there isn't a more simple solution...
    – F3L1X79
    Commented Sep 11, 2018 at 11:49
  • You can create an array of ids and place the modified feature ids there. Then each time you save you may empty the array. The example provided presents a way to catch the modified fetaure, there are several ways to achieve your goal but it depends on your logic
    – pavlos
    Commented Sep 12, 2018 at 10:59

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