ArcObjects Library Reference (GeoDatabase)  

ITopology Interface

Provides access to members that control a topology. Note: the ITopology interface has been superseded byITopology2. Please consider using the more recent version.

Product Availability

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


Method AddClass Add an object, feature, or attributed relationship class to the topology.
Read-only property Cache The topology graph of the topology.
Read-only property ClusterTolerance The cluster tolerance of the topology.
Read-only property DirtyArea The dirty area polygon of the topology.
Read-only property FeatureDataset The feature dataset that contains the topology.
Read-only property MaximumGeneratedErrorCount The maximum number of errors to generate when validating a topology.
Method RemoveClass Remove an object, feature, or attributed relationship class to the topology.
Read-only property State Indicates whether the topology is clean or not.
Read-only property TopologyID The ID of the topology.
Method ValidateTopology Validate the specified area in the topology.

CoClasses that implement ITopology

CoClasses and Classes Description
Topology Esri Topology object.


A Topology is a collection of simple feature classes within the same feature dataset that participate in topological relationships with a set of rules that govern those relationships.  Topologies can have multiple feature classes in the same topological role. A feature dataset may have multiple topologies but a feature class can only belong to one topology and only simple feature classes may participate in a topology.  Each topology has one associated topology graph. The topology graph is a planar representation of the geometries in the feature classes participating in a geodatabase topology.  If you need to access the topology graph directly for working with topology primitives such as edges and nodes, see the ITopologyGraph help.

When new features are created, edited or deleted, the topology is responsible for creating or modifying a dirty area that will encompass the envelope of the feature.  A dirty area is a special type of feature under which, the state of the topology is unknown.  Features that are covered by dirty areas can still be edited and queried, but their topological relationships cannot be guaranteed to be correct.  A dirty area must be validated in order to discover the topology of its underlying features and guarnatee their correctness.

.NET Related Topics

Checking for topology error features in a geodatabase topology | Creating a topology in the geodatabase | EditorExt | Geodatabase | Listening to the OnValidate event for a geodatabase topology | Working with topology errors