ArcGIS Pro 2.6 API Reference Guide
ExportToJSON Method (IGeometryEngine)
Example 

ArcGIS.Core.Geometry Namespace > IGeometryEngine Interface : ExportToJSON Method
A combination of JSONExportFlags which determines how the geometry is exported.
The input geometry to write to a string.
Writes a JSON version of the input geometry to a string.
Syntax
Function ExportToJSON( _
   ByVal exportFlags As JSONExportFlags, _
   ByVal geometry As Geometry _
) As String

Parameters

exportFlags
A combination of JSONExportFlags which determines how the geometry is exported.
geometry
The input geometry to write to a string.

Return Value

The JSON version of the input geometry.
Exceptions
ExceptionDescription
Geometry is null or empty.
The method is not implemented for GeometryBag.
Remarks
Note that if the geometry contains ID information, this property will not be preserved in the JSON string. ID is not part of the JSON specification.
Example
// MapPoint
string inputString = "{\"x\":1,\"y\":2,\"spatialReference\":{\"wkid\":4326,\"latestWkid\":4326}}";
Geometry geometry = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, inputString);

MapPoint importPoint = geometry as MapPoint;
// importPoint = 1, 2
// importPoint.SpatialReference.WKid = 4326

// use the MapPointBuilder convenience method
MapPoint importPoint2 = MapPointBuilder.FromJson(inputString);
// importPoint2 = 1, 2
// impointPoint2.SpatialReference.Wkid = 4326

string outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportDefaults, importPoint);
// outputString =  "{\"x\":1,\"y\":2,\"spatialReference\":{\"wkid\":4326,\"latestWkid\":4326}}"

string outputString2 = importPoint.ToJson();

inputString = "{\"spatialReference\":{\"wkid\":4326},\"z\":3,\"m\":4,\"x\":1,\"y\":2}";
importPoint = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, inputString) as MapPoint;
// importPoint.HasM = true
// importPoint.HasZ = true
// importPoint.X = 1
// importPoint.Y = 2
// importPoint.M = 4
// importPoint.Z = 3

importPoint2 = MapPointBuilder.FromJson(inputString);

// export to json - skip spatial reference
outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportSkipCRS, importPoint);
// outputString = "{\"x\":1,\"y\":2,\"z\":3,\"m\":4}"

// export from mappoint, skipping the sr - same as GeometryEngine.Instance.ExportToJSON w JSONExportFlags.jsonExportSkipCRS
outputString2 = importPoint.ToJson(true);

//
// Multipoint
//
List<Coordinate2D> coords = new List<Coordinate2D>()
{
  new Coordinate2D(100, 200),
  new Coordinate2D(201, 300),
  new Coordinate2D(301, 400),
  new Coordinate2D(401, 500)
};

Multipoint multipoint = MultipointBuilder.CreateMultipoint(coords, SpatialReferences.WebMercator);

inputString = "{\"points\":[[100,200],[201,300],[301,400],[401,500]],\"spatialReference\":{\"wkid\":3857}}";
Multipoint importMultipoint = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, inputString) as Multipoint;
// importMultipoint.IsEqual(multipoint) = true

ReadOnlyPointCollection points = importMultipoint.Points;
// points.Count = 4
// points[0] = 100, 200
// points[1] = 201, 300
// points[2] = 301, 400
// points[3] = 401, 500

// use the Multipointbuilder convenience method
Multipoint importMultipoint2 = MultipointBuilder.FromJson(inputString);
// importMultipoint2.IsEqual(multipoint) = true

// export to json
outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportDefaults, multipoint);
// outputString = inputString

// or use the multipoint itself
outputString2 = multipoint.ToJson();

//
// Polyline
//
Polyline polyline = PolylineBuilder.CreatePolyline(coords, SpatialReferences.WebMercator);

// export without the spatial reference
outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportSkipCRS, polyline);
// import
geometry = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, outputString);
Polyline importPolyline = geometry as Polyline;
// importPolyline.SpatialReference = null


points = importPolyline.Points;
// points.Count = 4
// points[0] = 100, 200
// points[1] = 201, 300
// points[2] = 301, 400
// points[3] = 401, 500

// use the polylineBuilder convenience method 
Polyline importPolyline2 = PolylineBuilder.FromJson(outputString);
// importPolyline2 = importPolyline

outputString2 = importPolyline2.ToJson();
// outputString2 = outputString

//
// Polygon
//
Polygon polygon = PolygonBuilder.CreatePolygon(coords, SpatialReferences.WebMercator);

// export without the spatial reference
outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportSkipCRS, polygon);
// import
geometry = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, outputString);

Polygon importPolygon = geometry as Polygon;
// importPolygon.SpatialReference = null
points = importPolygon.Points;
// points.Count = 5

// polygonBuilder convenience method
Polygon importPolyon2 = PolygonBuilder.FromJson(outputString);
// importPolygon2 = importPolygon

// export from the polygon
outputString2 = importPolyon2.ToJson(true);

// Empty polygon
polygon = PolygonBuilder.CreatePolygon(SpatialReferences.WebMercator);
outputString = GeometryEngine.Instance.ExportToJSON(JSONExportFlags.jsonExportDefaults, polygon);
importPolygon = GeometryEngine.Instance.ImportFromJSON(JSONImportFlags.jsonImportDefaults, outputString) as Polygon;

// importPolygon.IsEmpty = true
// importPolygon.SpatialReference.Wkid = 3857
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

IGeometryEngine Interface
IGeometryEngine Members