How to remove points on the Openlayers map?

Question

I am experimenting with openlayers. I am adding points to the map using this example. However, I also want to delete unwanted points from the map. For example, I clicked 6 points on the map and I want to remove the fifth point, but keep 1, 2, 3, 4, and 6 th point on the map. How can I do this in openLayers. So far, I tried this example and this example, but I had no luck so far. Please help me out.

Update: I have the following JsFiddle shows the code to add points to my map. I want to remove one point, but keep the rest of them on the map.

var raster = new ol.layer.Tile({
    source: new ol.source.OSM()
  });

  var map = new ol.Map({
    layers: [raster],
    target: 'map',
    view: new ol.View({
      center: [-11000000, 4600000],
      zoom: 4
    })
  });

  var features = new ol.Collection();
  var featureOverlay = new ol.layer.Vector({
    source: new ol.source.Vector({features: features}),
    style: new ol.style.Style({
      fill: new ol.style.Fill({
        color: 'rgba(255, 255, 255, 0.2)'
      }),
      stroke: new ol.style.Stroke({
        color: '#ffcc33',
        width: 2
      }),
      image: new ol.style.Circle({
        radius: 7,
        fill: new ol.style.Fill({
          color: '#ffcc33'
        })
      })
    })
  });
  featureOverlay.setMap(map);

  var modify = new ol.interaction.Modify({
    features: features,
    // the SHIFT key must be pressed to delete vertices, so
    // that new vertices can be drawn at the same position
    // of existing vertices
    deleteCondition: function(event) {
      return ol.events.condition.shiftKeyOnly(event) &&
          ol.events.condition.singleClick(event);
    }
  });
  map.addInteraction(modify);

  var draw; // global so we can remove it later
  var typeSelect = document.getElementById('type');

  function addInteraction() {
    draw = new ol.interaction.Draw({
      features: features,
      type: /** @type {ol.geom.GeometryType} */ (typeSelect.value)
    });
    map.addInteraction(draw);
  }


  /**
   * Handle change event.
   */
  typeSelect.onchange = function() {
    map.removeInteraction(draw);
    addInteraction();
  };

  addInteraction();

Update 2: I can remove the last element using removeLastPoint() inside ol.interaction.Draw.

Answer 1

The third example you linked to covers this pretty nicely I think.

You need to add another interaction - a select interaction - to allow selection of a feature when it's clicked. Something like the following -

var selectInteraction = new ol.interaction.Select();
map.addInteraction(selectInteraction);

Then you need to add some kind of event (like the user clicking a "Delete" button). In the handler for that event, you can use the following code to delete the feature:

//Get the feature that's selected
var selectedFeature = selectInteraction.getFeatures().item(0);
//Remove it from your feature source
featureOverlay.getSource().removeFeature(selectedFeature)

Answer 2

We can create a new variable as sourceVector.
var sourceVector = new ol.source.Vector({features: features})

Then on this line source: new ol.source.Vector({features: features}),

change it to source: sourceVector,

So now if you use sourceVector.removeFeature(sourceVector.getFeatures()[4]); it would remove the fifth point in the array.