ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Geometry Namespace / GeometryEngine Class / GeodesicBuffer Method / GeodesicBuffer(IEnumerable<Geometry>,Double,LinearUnit) Method
Specifies the input geometries.
The distance to buffer the geometries.
The unit of the buffer distance. If null, then the buffer distance is in meters.
Example Version

GeodesicBuffer(IEnumerable<Geometry>,Double,LinearUnit) Method
Creates buffers at the specified distance around the given geometries. Will union the results of all buffers.
Syntax

Parameters

geometries
Specifies the input geometries.
distance
The distance to buffer the geometries.
distanceUnit
The unit of the buffer distance. If null, then the buffer distance is in meters.

Return Value

The polygon that represents the buffered area.
Exceptions
ExceptionDescription
Geometries is null.
Geometries have no spatial reference.
At least one of the geometries is null.
The method is not implemented for GeometryBag.
The first non-null spatial reference is an image coordinate system.
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 = new List<MapPoint>();
list.Add(MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84));
list.Add(MapPointBuilderEx.CreateMapPoint(10.0, 20.0));
list.Add(MapPointBuilderEx.CreateMapPoint(40.0, 40.0));
list.Add(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 List<Coordinate2D>()
{
  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 = new List<Geometry>
{
  MapPointBuilderEx.CreateMapPoint(1.0, 1.0, SpatialReferences.WGS84),
  PolylineBuilderEx.CreatePolyline(new List<Coordinate2D>(){coords[0], coords[1], coords[2]}, SpatialReferences.WGS84),
  PolylineBuilderEx.CreatePolyline(new List<Coordinate2D>(){coords[3], coords[4], coords[5]}),
  PolygonBuilderEx.CreatePolygon(new List<Coordinate2D>(){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, Windows 10

ArcGIS Pro version: 3 or higher.
See Also