[GIS] How to get line and polygon points from OpenLayers 3 drawing

javascriptopenlayers

I am working on drawing points/segments/polygons on a map that uses OpenLayers 3. The first part I have done draws points, lines and polygons. Now I am trying to retrieve the drawn coordinates in order to build them for other sessions.

I have been able to getting just coordinate for the point/image, but can't get coordinates for segment/polygon. Any ideas or help? I've included a JSfiddle below

https://jsfiddle.net/Lg8w71kv

Best Answer

What you're looking for is the drawend event that is fired by the ol.interaction.Draw object you created. If you hook into it, you will get back the feature that has been drawn. See the fiddle below:

https://jsfiddle.net/Lg8w71kv/1/

Related Solutions

OpenLayers Coordinates – How to Get the Start and End Points of a Line in OL3

why dont you get the feature drawn and then get the coordinates out of it. It should be much faster.

draw.on('drawend', function(e2) {
var feature = e2.feature;
var geometry = feature.getGeometry();

//depending on the type of geometry drawn you may get first and last 
//coordinate. From your description I guess you draw a linestring 
//you may clarify that using geometry.getType()
//so for ol.geom.LineString do as follows. According to the 
//documentation this should work for any type of geometries
var startCoord = geometry.getFirstCoordinate();
var endCoord = geometry.getLastCoordinate();
//If you are not sure what the type is, or if you face any problems 
//with getFirstCoordinate, getLastCoordinate
//you may go for a more general technique

var coordinates = geometry.getCoordinates();
//and then parse the coordinates object to get first and last
var startCoord = coordinates[0];
var endCoord = coordinates[coordinates.length-1];
});

[GIS] Use a second canvas for drawing an animation in Openlayers

Have you give ol-ext a try? They have a lot of cool stuff you can do on the map and this way you won't require an additional canvas or transparent layers.

The closest thing I can see they have that might work for you is this one here.

Best Answer

Related Solutions

OpenLayers Coordinates – How to Get the Start and End Points of a Line in OL3

[GIS] Use a second canvas for drawing an animation in Openlayers

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