Topology describes the way interrelated features are organized and connected. In ArcGIS Pro, it is implemented as a collection of spatial rules that are used to constrain active edits or audit and maintain the correctness of features based on their position relative to other features.
There are two types of topology in ArcGIS Pro: topological editing and geodatabase topology. You can use one or both to help you manage and maintain the accuracy of your feature data with respect to coincidence, adjacency, containment, and connectivity.
Topological editing is an editing mode that constrains coincident geometry to an ordered graph of topologically connected edges and nodes. It requires no setup and operates only on visible features that are editable.
Working with geodatabase topology includes creating a topology for a dataset, assigning features and spatial rules, validating the features in a map, and using specific tools to fix errors and mark exceptions.
Located on the Edit tab in the Manage Edits group, you can turn topological editing on and off as you modify features. Map Topology operates on all features. Choosing a geodatabase topology rule limits topological editing to features participating in the selected rule.
Many features in S-57 and S-100 share topological relationships with one another, which must be maintained to satisfy industry standards for data validation. An example of this is the coincidence of the coastline, land, and the sea. The land areas cannot cross over the coastline, or the depth areas; conversely, depth areas cannot cross land areas or the coastline.
In scenarios in which you are editing these types of features, you can use geodatabase topology to ensure these topological rules are followed. When you edit using a geodatabase topology, you can edit a single feature and have all features that participate in a topological relationship update automatically.
Topological constraints are applied by means of a topological graph. The graph appears as a highlighted network of edges and nodes over the features you are editing. Edges define shared linear boundaries, and nodes define connectivity across endpoints and intersections.
Turning on topological editing makes the graph available to editing tools and shows an Edges tab on tools that can perform both feature and topological edits. Editing an edge or a node modifies the corresponding feature geometry; for example, moving a shared edge also stretches any connected segments.
The connectedness of your changes is validated when you Finish your edits. If they break the topological graph, the message Edit operation failed appears and your changes are canceled.