How to draw ellipse in OpenLayers? I have not problems with drawing circles, or MultiPolygons, but i need to draw simple ellipse and not found any functions for this action.
[GIS] Drawing ellipse in OpenLayers
ellipseopenlayers
Related Solutions
I've done similar work before, for rotation, there is rotate function for polygons. In your case, add following line before adding feature to the layer:
var originPoint = new OpenLayers.Geometry.Point(xCent, yCent).transform(map.displayProjection, map.projection); //center point for rotation
polygonFeature.geometry.rotate(rot, originPoint);
You can find full documentation about rotate function here
I'm not sure about your calculation for the ellipses(you might have used some mathematical transformations), but I would suggest to use the polar system to get those points coordinates.
Get the distance from the point on ellipse at direction θ to the origin using following formula:
The coordinates of the point are:
x = r(θ) * cos(θ)
y = r(θ) * sin(θ)
You can use something like this -
var features = vectorSource.getFeatures();
var lastFeature = features[features.length - 1];
vectorSource.removeFeature(lastFeature);
Note that you need to vectorSource.getFeatures() every time you want to remove the last feature or use it in a function.
Best Answer
Try this extension example -->
http://viglino.github.io/ol-ext/examples/interaction/map.interaction.drawregular.html
Use a number less than three and you will be able to draw an ellipses.
Here is the api -->http://viglino.github.io/ol-ext/doc/doc-pages/ol.interaction.DrawRegular.html