CODEWITHSUNDEEP
openlayers-3
Artturi
Artturi

Reputation: 63

How to get coordinates of a user-drawn circle in Openlayers 3?

I have a static image layer in Openlayers3 where user can draw features like circle, point and polygon.

I can get coordinates of Point, Polygon and LineString with this code:

draw_interaction.on('drawend', function(event) {
    var geoJsonGeom = new ol.format.GeoJSON();    
    var pp = geoJsonGeom.writeGeometry(event.feature.getGeometry());
    console.log(pp);
});

This outputs coordinates as expected:

"{"type":"Point","coordinates":[1441.9187662124637,1365.3125032424925]}"

However, I can't figure out how to get coordinates of a Circle. The output in the case of Circle looks like this:

"{"type":"GeometryCollection","geometries":[]}"

Openlayers version is v3.5.0.

EDIT: in order to get center and radius you must use feature itself, not its GeoJSON output (since GeojSON does not have circle):

var circle = event.feature.getGeometry();
console.log('radius:' + circle.getRadius());
console.log('center:' + circle.getCenter());

Upvotes: 3

Views: 5440

Answers (3)

tomW
tomW

Reputation: 191

For all developer searching for a solution to get coordinates out of a circle:

The class "Polygon" got a method called "fromCircle". Up from there you can use .getCoordinates()

https://openlayers.org/en/latest/apidoc/module-ol_geom_Polygon.html#.fromCircle

Its also available int v3.6.0 http://www.scgis.net/api/ol/v3.6.0/apidoc/ol.geom.Polygon.html

Upvotes: 0

sumit
sumit

Reputation: 1

draw_interaction.on('drawend', function(event) {
    var geoJsonGeom = new ol.format.GeoJSON();    
    var pp = geoJsonGeom.writeGeometry(event.feature.getGeometry());
    console.log(pp);
});

Works well

Upvotes: -1

bartvde
bartvde

Reputation: 2126

GeoJSON does not have circle geometries. The proper solution would be to approximate the circle with a polygon before serialisation. You might be able to achieve this with the new geometry option of ol.interaction.Draw see: https://github.com/openlayers/ol3/pull/3673 See also this github issue for some deeper discussion on the subject: https://github.com/openlayers/ol3/pull/3434

Upvotes: 2

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