topic Re: how to create and display and ellipse on the map in ArcObjects SDK Questions

how to create and display and ellipse on the map

DarrenRempel — Tue, 17 Aug 2010 11:58:23 GMT

I am trying to create and display an ellipse from the user selecting 2 points using the NewEllipseFeedbackClass but am not having any luck. Here is the code I am using:
EllipticArcClass ellipticalArc = new EllipticArcClass();
                    IEnvelope env = new EnvelopeClass();
                    IPoint lowerLeft = new PointClass();
                    lowerLeft.X = centerPoint.X - width;
                    lowerLeft.Y = centerPoint.Y - height;
                    IPoint upperRight = new PointClass();
                    upperRight.X = centerPoint.X + width;
                    upperRight.Y = centerPoint.Y + height;
                    env.LowerLeft = lowerLeft;
                    env.UpperRight = upperRight;

                    ellipticalArc.ConstructEnvelope(env);
                    IGraphicTrackerSymbol graphicTrackerSymbol = this.graphicTracker.CreateSymbol(simpleFillSymbol, null);

                    int shapeId = this.graphicTracker.Add(ellipticalArc, graphicTrackerSymbol);

I have tried some of the other methods such as PutCoords and PutCoordsbyAngle but was unable to get them to work. Anyone have any hints on how to do this?

Re: how to create and display and ellipse on the map

DanielTuracek — Thu, 19 Aug 2010 07:02:48 GMT

look here
http://forums.esri.com/Thread.asp?c=93&f=993&t=142088

or here

http://forums.esri.com/Thread.asp?c=93&f=992&t=85896

Re: how to create and display and ellipse on the map

DarrenRempel — Fri, 20 Aug 2010 12:45:41 GMT

interesting - my code works when dynamic display is turned off but does NOT work with dynamic display turned on! also, if you try and use any of the built in drawing commands such as ControlsNewEllipseTool or ControlsNewCircleTool - they don't work in dynamic display.

Re: how to create and display and ellipse on the map

DarrenRempel — Fri, 20 Aug 2010 16:14:57 GMT

here's a 'workaround' for dynamic display:

//create your EllipticArcClass as you would according to the ESRI documentation then get
//the points that make up the ellipse and create a polygon based on it - not efficient but it works

List<PointClass> points = new System.Collections.Generic.List<PointClass>();
//the level of fidelity should be adjusted
for(double d = 0.1; d < ellipticalArc.Length; d += 0.1)
{
PointClass p = new PointClass();
ellipticalArc.QueryPoint(esriSegmentExtension.esriNoExtension, d, false, p);
   points.Add(p);
}

polygon = new PolygonClass();
foreach (PointClass p in points)
     polygon.AddPoint(p);

ITopologicalOperator topo = polygon as ITopologicalOperator;
    topo.Simplify();

//added polygon using graphicTracker and simplefillsymbol