ArcObjects Library Reference  (Geometry)    

IGeometry Interface

Provides access to members that describe properties and behavior of all geometric objects. Note: the IGeometry interface has been superseded by IGeometry5. Please consider using the more recent version.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.


Common properties and methods shared by all geometric objects.  Geometries are objects that define a spatial location and an associated geometric shape.


Read-only property Dimension The topological dimension of this geometry.
Read-only property Envelope Creates a copy of this geometry's envelope and returns it.
Read-only property GeometryType The type of this geometry.
Method GeoNormalize Shifts longitudes, if need be, into a continuous range of 360 degrees.
Method GeoNormalizeFromLongitude Normalizes longitudes into a continuous range containing the longitude. This method is obsolete.
Read-only property IsEmpty Indicates whether this geometry contains any points.
Method Project Projects this geometry into a new spatial reference.
Method QueryEnvelope Copies this geometry's envelope properties into the specified envelope.
Method SetEmpty Removes all points from this geometry.
Method SnapToSpatialReference Moves points of this geometry so that they can be represented in the precision of the geometry's associated spatial reference system.
Read/write property SpatialReference The spatial reference associated with this geometry.

CoClasses that implement IGeometry

CoClasses and Classes Description
BezierCurve A cubic Bezier curve defined between two points; optionally has measure, height and ID attributes at each endpoint.
CircularArc A portion of a circle that connects two points optionally has measure, height and ID attributes at each endpoint.
EllipticArc A portion of the boundary of a 2D ellipse that connects two points; optionally has measure, height and ID attributes at each endpoint.
Envelope A rectangle with sides parallel to a coordinate system defining the extent of another geometry; optionally has min and max measure, height and ID attributes.
GeoEllipse (esriDefenseSolutions) A spheroidal ellipse.
GeometryBag An ordered collection of objects that support the IGeometry interface.
GeoPolygon (esriDefenseSolutions) A spheroidal polygon.
GeoPolyline (esriDefenseSolutions) A spheroidal polyline.
Line A 2D straight line between a pair of 2D endpoints; can optionally have height, measure and ID attributes at each endpoint.
MultiPatch A collection of surface patches.
Multipoint An ordered collection of points; optionally has measure, height and ID attributes.
Path A sequence of connected segments.
Point A two dimensional point, optionally with measure, height, and ID attributes.
Polygon A collection of rings ordered by their containment relationship; optionally has measure, height and ID attributes.
Polyline An ordered collection of paths; optionally has measure, height and ID attributes.
Ray A 3D ray that begins at a point and extends infinitely along a line in one direction only.
Ring An area bounded by one, closed sequence of connected segments; optionally has measure, height and ID attributes at each vertex.
Sphere A complete sphere.
TriangleFan A continuous 3D fan of triangles, where each triangle after the first shares an edge with the preceding triangle, and all triangles share a common pivot point.
Triangles A collection of 3D triangles, where each consecutive triplet of vertices defines a new triangle
TriangleStrip A continuous 3D strip of triangles, where each triangle after the first shares an edge with the preceding triangle.


Every Geometry created within ArcGIS should be assigned a spatial reference. Always attach well-defined spatial references to new geometries. This improves processing efficiency, in particular, when using ITopologicalOperator on geometries that contain curved segments (circular arcs, bezier curves, elliptical arcs). New geometries include any geometry that is created in memory. It does not matter whether it will be stored in a feature class or not. Well-defined as applied to a spatial reference means that it not only has its coordinate system (projection) defined, but also its coordinate grid. The coordinate grid consists of the xy domain, xy resolution, and xy cluster tolerance properties of a spatial reference. If the Geometry includes z or m values, the z or m domains, z or m resolutions, and z or m cluster tolerance properties must also be defined. The cluster tolerance and resolutions can be quickly and easily set using SetDefault methods on ISpatialReferenceResolution and ISpatialReferenceTolerance interfaces.