topic Re: How do we find out the angle of a geometry (Rectangle) on a map. in .NET Maps SDK Questions

How do we find out the angle of a geometry (Rectangle) on a map.

BikeshMaharjan1 — Wed, 23 Aug 2017 16:45:29 GMT

Trying to find out if it is possible to find out angle of a geometry: Rectangle geometry in my case.

Thanks,

Bikesh

Re: How do we find out the angle of a geometry (Rectangle) on a map.

dotMorten_esri — Wed, 23 Aug 2017 18:14:34 GMT

A polygon doesn't really have an "angle". You could make the assumption that if your polygon has 4 vertices, it's a rectangle. Then you need to make an assumption about which vertex is at which index (ie if it's rotated 0 degrees, is index 0 the lower-left vertex?).

Once you do that, you could take two consecutive vertices and use trigonometry to calculate an angle.

So you would end up with something along the lines of this:

MapPoint firstVertex = polygon.Parts[0][0].StartPoint;
            MapPoint secondVertex = polygon.Parts[0][0].EndPoint;
            double xDiff = secondVertex.X - firstVertex.X;
            double yDiff = secondVertex.Y - firstVertex.Y;
            double angle = Math.Atan2(yDiff, xDiff) * 180.0 / Math.PI;

Re: How do we find out the angle of a geometry (Rectangle) on a map.

BikeshMaharjan1 — Thu, 24 Aug 2017 15:17:05 GMT

Thank you Morten. That was really helpful. Do you know if there is a way to draw a rectangle given just length, width, centerpoint of rectangle and may be angle?

Thanks,

Bikesh

Re: How do we find out the angle of a geometry (Rectangle) on a map.

dotMorten_esri — Thu, 24 Aug 2017 15:46:51 GMT

There's nothing out of the box, but you have everything needed to use a little trigonometry and math to figure out where the 4 vertices go.