How to create a circle with ArcEngine?

Question

I want to create a circle with IPoint P and radius r in ArcEngine and then I need to cast it to an IGeometry. Does anyone know how to do this?

ESRI ArcEngine 10 VS2010 C#

Answer 1

found it

ISegmentCollection p = new PolygonClass();
p.SetCircle(mousepoint, 20);
IGeometry circleGeo = p as IGeometry;

Answer 2

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);

Answer 3

Another method is to cast your point to ITopologicalOperator and use the Buffer method to buffer the point by the radius.

Answer 4

I prefer the ISegmentCollection solution myself, but you can also recast your IPoint or IGeometry as ITopologicalOperator and call the Buffer method.