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I have a GIS API that uses the OpenLayers 2.13 measure and drawFeature controls. But let's just talk about the measure control, because the issues are certainly connected.

As I show in this CodePen, the measure control is supposed to show the immediate measures, i.e., print them on mouse move.

measureControl = new OpenLayers.Control.Measure(OpenLayers.Handler.Path, measureControlOptions);

map.addControl(measureControl);

measureControl.events.register('measure', measureControl, function(e) {
    printOutput(e);
});

measureControl.events.register('measurepartial', measureControl, function(e) {
    printOutput(e);
});

Of course, when I use this example in a touch device, I can't use the onmousemove event. Instead, the behaviour is like this:

  • 1st tap to start measuring
  • 2nd tap to stop measuring

It shows the desired length, but I am not able to perform an accurate measurement because I want to see the measures as I move my finger on the touch screen.

I am not very familiar with touch events, so I apologize if this is a stupid question. but is there an easy way to mimic the mouse behaviour on the touch device?

The desired behaviour is something like:

  • tap down --> starts measuring
  • tap move (without lifting the finger) --> keeps measuring and show the new measurement on each move
  • tap up --> stops the measurement
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I guess you have to listen to the touchmove event but havent tested this before.

If it does not have to be measuring by touchmove you could habe a look at this example with an optimized measure-control for mobile devices.

http://rawgit.com/pgiraud/OL-MobileMeasure/master/examples/mobile-measure.html

enter image description here

UPDATE1: just gave it a try and it works. You can take the event-pixel-value of the touchmove event and use it in combination with map.getLonLatFromLayerPx(e.xy) to get a new vertex point for the line.

Here you can find two working examples:

http://rawgit.com/neogis-de/OL_MobileMeasuring/master/index.html

http://rawgit.com/neogis-de/OL_MobileMeasuring/master/index2.html

(with 5px shift so you can see the end of the measuring line)

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