GeodesicBuffer(IEnumerable<Geometry>,Double) Method

In This Topic

Creates buffers at the specified distance around the given geometries. Will union the results of all buffers.

Syntax

Visual Basic (Declaration)
C#

Overloads Function GeodesicBuffer( _
   ByVal geometries As IEnumerable(Of Geometry), _
   ByVal distance As Double _
) As Geometry

Geometry GeodesicBuffer( 
   IEnumerable<Geometry> geometries,
   double distance
)

Parameters

geometries: Specifies the input geometries.
distance: The distance (in meters) to buffer the geometries.

Return Value

The polygon that represents the buffered area.

Exceptions

Exception	Description
System.ArgumentNullException	Geometries is null or empty
System.NotImplementedException	The method is not implemented for GeometryBag.
System.ArgumentException	Geometries have no spatial reference.
System.NotImplementedException	The first non-null spatial reference is an image coordinate system.
System.ArgumentException	The buffer distance must be a valid floating point number.

Remarks

At least one geometry must have a spatial reference that is not null or Unknown. The spatial reference of the output geometries is the first valid spatial reference found in the list of geometries. All other geometries are projected to this spatial reference, if necessary. The returned polygon is the union of all the buffered geometries.

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

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 created.

Example

Create a buffer polygon at the specified geodesic distance

{
    // buffer a point
    MapPoint pt = MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84);
    Polygon outPolygon = GeometryEngine.Instance.GeodesicBuffer(pt, 5) as Polygon;

    double delta = SpatialReferences.WGS84.XYTolerance * 2 * Math.Sqrt(2);
    ReadOnlyPointCollection points = outPolygon.Points;
    foreach (MapPoint p in points)
    {
      double d = GeometryEngine.Instance.GeodesicDistance(pt, p);
      // d = 5 (+- delta)
    }

    // specify a unit for the distance
    outPolygon = GeometryEngine.Instance.GeodesicBuffer(pt, 5000, LinearUnit.Millimeters) as Polygon;

    // buffer of 0 distance produces an empty geometry
    Geometry g = GeometryEngine.Instance.GeodesicBuffer(pt, 0);
    // g.IsEmpty = true

    // buffer many points
    List<MapPoint> list =
    [
      MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84),
  MapPointBuilderEx.CreateMapPoint(10.0, 20.0),
  MapPointBuilderEx.CreateMapPoint(40.0, 40.0),
  MapPointBuilderEx.CreateMapPoint(60.0, 60.0),
];

    outPolygon = GeometryEngine.Instance.GeodesicBuffer(list, 10000) as Polygon;
    // outPolygon.PartCount = 4

    // buffer different geometry types
    List<Coordinate2D> coords =
    [
      new Coordinate2D(1, 2), new Coordinate2D(10, 20), new Coordinate2D(20, 30),
  new Coordinate2D(50, 60), new Coordinate2D(70, 80), new Coordinate2D(80, 40),
  new Coordinate2D(90, 10), new Coordinate2D(110, 15), new Coordinate2D(120, 30),
  new Coordinate2D(10, 40), new Coordinate2D(-10, 40), new Coordinate2D(-10, 50)
    ];

    List<Geometry> manyGeometries =
    [
      MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84),
  PolylineBuilderEx.CreatePolyline([coords[0], coords[1], coords[2]], SpatialReferences.WGS84),
  PolylineBuilderEx.CreatePolyline([coords[3], coords[4], coords[5]]),
  PolygonBuilderEx.CreatePolygon([coords[9], coords[10], coords[11]])
    ];

    outPolygon = GeometryEngine.Instance.GeodesicBuffer(manyGeometries, 20000) as Polygon;

    // specify unit types
    outPolygon = GeometryEngine.Instance.GeodesicBuffer(manyGeometries, 20, LinearUnit.Miles) as Polygon;
  }

Requirements

Target Platforms: Windows 11 Home, Pro, Enterprise (64 bit)

ArcGIS Pro version: 3.0 or higher.

Reference

IGeometryEngine Interface
IGeometryEngine Members
Overload List

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