An overview of topology in ArcGIS

If you have features that are coincident and share the same location of coordinates, boundaries, or nodes, chances are that geodatabase topology can help you better manage your geographic data.

Geodatabase topologies help you ensure data integrity. Using a topology provides a mechanism to perform integrity checks on your data and helps you to validate and maintain better feature representations in your geodatabase.

In addition, you can use topologies for modeling numerous spatial relationships between features. These enable support for a variety of analytic operations, such as finding adjacent features, working with coincident boundaries between features, and navigating along connected features.

Topological relationships

Topology is the arrangement for how point, line, and polygon features share geometry. Topology is employed to do the following:

• Constrain how features share geometry. For example, adjacent polygons such as parcels have shared edges, street centerlines and census blocks share geometry, and adjacent soil polygons share edges.
• Define and enforce data integrity rules: no gaps should exist between polygons, there should be no overlapping features, and so on.
• Support topological relationship queries and navigation, such as to identify feature adjacency and connectivity.
• Support sophisticated editing tools that enforce the topological constraints of the data model.
• Construct features from unstructured geometry, such as to create polygons from lines.

The process of building a topology from existing data can be summarized in the following steps:

Topology workflows and tasks

Tasks	Links for more information
Design your topology.	See Designing a geodatabase topology.
Create a set of feature classes within a common feature dataset in a geodatabase.	See An overview of working with feature datasets.
If you have existing feature data, load these into your feature classes.	See About importing feature classes.
Create the topology using ArcCatalog or geoprocessing tools.	See Creating a topology.
Build and validate your topology.	See Validating a topology.
Add the topology to ArcMap and set its display properties.	See Drawing and displaying topologies in ArcMap.
Use the editing environment to identify and fix errors.	See Editing a topology.
Manage updates to feature classes and manage dirty areas.	See Validating a topology.
Manage topology within a versioned geodatabase.	See Topology and versioned geodatabases.
Perform many other common editing tasks.	See Common topology tasks.