Buffer(Geometry,Double) Method

In This Topic

Creates a buffer polygon at the specified distance around the given geometry.

Syntax

C#
Visual Basic (Declaration)

public Geometry Buffer( 
   Geometry geometry,
   double distance
)

Public Overloads Function Buffer( _
   ByVal geometry As Geometry, _
   ByVal distance As Double _
) As Geometry

Parameters

geometry: Specifies the input geometry.
distance: The distance (in the unit of the geometry's spatial reference) to buffer the geometry.

Return Value

The polygon that represents the buffered area.

Exceptions

Exception	Description
System.ArgumentNullException	Geometry is null or empty.
System.NotImplementedException	The method is not implemented for GeometryBag.
System.ArgumentException	The buffer distance must be a valid floating point number.

Remarks

If the buffer distance is zero and the input geometry is a polygon or an envelope, then a polygon created from the input geometry is returned.

If the distance is less than or equal to zero and the input geometry is not a polygon or an envelope, then an empty polygon is returned.

GeometryEngine Buffer

Example

Zoom to a specified point

//Create a point
var pt = MapPointBuilderEx.CreateMapPoint(x, y, 
               SpatialReferenceBuilder.CreateSpatialReference(4326));
//Buffer it - for purpose of zoom
var poly = GeometryEngine.Instance.Buffer(pt, buffer_size);

//do we need to project the buffer polygon?
if (!MapView.Active.Map.SpatialReference.IsEqual(poly.SpatialReference))
{
  //project the polygon
  poly = GeometryEngine.Instance.Project(poly, MapView.Active.Map.SpatialReference);
}

// Must run on MCT.
QueuedTask.Run(() =>
{
  //Zoom - add in a delay for animation effect
  MapView.Active.ZoomTo(poly, new TimeSpan(0, 0, 0, 3));
});

Buffer a MapPoint

// buffer a point
MapPoint pt = MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84);
Geometry ptBuffer = GeometryEngine.Instance.Buffer(pt, 5.0);
Polygon buffer = ptBuffer as Polygon;

Buffer a Circular Arc

// create the circular arc
MapPoint fromPt = MapPointBuilderEx.CreateMapPoint(2, 1);
MapPoint toPt = MapPointBuilderEx.CreateMapPoint(1, 2);
Coordinate2D interiorPt = new Coordinate2D(1 + Math.Sqrt(2) / 2, 1 + Math.Sqrt(2) / 2);

EllipticArcSegment circularArc = EllipticArcBuilderEx.CreateCircularArc(fromPt, toPt, interiorPt);

// buffer the arc
Polyline polyline = PolylineBuilderEx.CreatePolyline(circularArc);
Geometry lineBuffer = GeometryEngine.Instance.Buffer(polyline, 10);

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

GeometryEngine Class
GeometryEngine Members
Overload List

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