A nuget will be available soon.

This library aims to augment interoperability between ESRI ArcObjects and other projects. It provides custom JsonConverters for Newtonsoft.Json to export IGeometry objects to different json formats.

ArcObjects are COM components with parameterless constructors, they cannot enforce strict format rules nor object constraints. Therefore, a geometry might be incomplete, incoherent or simply empty depending of where and how it was created. Also, IPolygon or IPolyline (but strangely not IPoint) can always become multi-parts by adding geometries to its collection without altering its geometry type. More over, IMultiPoint can be empty or contain a single point.

The converters work hard to make the serialization go as smooth and predictable as possible and always assume the worst case scenario: a half baked geometry.

Before serializing a geometry to json, a converter could (depending on GeoJsonSerializerSettings):

• serialize empty geometries as null
• remove paths with less than 2 points
• remove rings with less than 4 points
• change non-simple geometries to simple ones
• auto-correct self-intersections and segment overlaps
• adjust ring orientations: counter clock-wise for exterior rings, clock-wise for holes
• downgrade the geometry type to its "proper" value (see conversion table below)
• generalize paths/rings containing true curves when appropriate

At last, if nothing can be done to serialize the geometry, the converter will complain by throwing an exception.

• invalid: denotes a state not appropriate for the type being serialized. For example:

  • a path with a single point
  • a path or ring length smaller than Tolerance
  • a ring with less than 4 coordinates
  • an unclosed ring
  • a polygon without an exterior ring
  • an empty geometry part

Using ForceMulti=false will make the serializer ajust to input geometries. If a Multipoint, Polyline or Polygon contains a single part, the serializer will write a GeoJSON type of Point, LineString or Polygon.

If ForceMulti=true, all ArcObjects types will always be serialized as Multi*, even if they contain a single part, because ArcObjects does not make a distinction between single and multi-parts (excepting Point).

Using Simplify=true will use ITopologicalOperator.Simplify() before serializing a geometry. Simplify may remove duplicate geometry parts and may reorient segments in paths and rings. See the official ESRI documentation for this setting.

Notes:

• * Invalid parts are always removed.
• ** Polygon serialized without a hole

When true curves are present in Polyline and Polygon, the geometry is always generalized, even with Simplify=false. This will eventually be adjusted to only generalize the curved segments.

This project is open source under the MIT license.