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Introduction to editing topology

On the Edit tab, in the Manage Edits group, Map Topology Map Topology turns map topology on or off in the active map. Topological editing automatically modifies adjacent features that share coincident geometry and preserves their connectivity when you finish your edits.

If you attempt to finish edits that break the topology connectivity, the message Edit operation failed Error appears, and your changes are canceled.

Topology settings

You can prevent topological editing for a visible layer by turning off editability in the Contents pane, on the List By Editing tab List By Editing. When features participate in a geodatabase topology, choosing a topology rule limits topological editing to only the layers defined by the rule.

Editing tools

When you enable map topology, Features and Edges tabs appear on editing tools that move, reshape, or edit vertices. These tools can modify finished features or modify their individual edges. Clicking a tab finishes the current edit and switches the editing mode.

For example, clicking the Features tab and moving a polygon feature moves the entire feature and stretches other segments connected to it. Clicking the Edges tab moves a topological edge of the feature, changing the shape of the polygon and stretching any topological edges connected to it.

For a list of editing tools that can edit topological elements, see Modify Features tool reference.

Edges and nodes

Map topology requires no setup. It uses edges and nodes to define and maintain simple relationships such as coincidence, covering, and crossing of feature geometry. All visible simple features can participate in a map topology at any time.

When you topologically edit feature geometry, its topology appears as a highlighted graph of edges and nodes that correlate directly to the features you are editing. An edge is defined by a polyline or polygon boundary. A node defines edge endpoints and intersections as well as point features.

Edges and nodes are summarized in the following table.

Simple featureTopology element

Point

  • Points have node behavior when they are coincident with other features in a topology.

Polyline or polygon

  • An edge is defined by a linear boundary.
  • Two nodes define the endpoints of an edge.
  • Vertices define the shape of an edge between two nodes.
  • Nodes also define edge intersections.

Cluster tolerance options

On the Map Topology Options dialog box, the cluster tolerance is the distance within which edges and vertices are determined to be coincident. By default, ArcGIS Pro automatically calculates a minimum possible value. You can specify a custom tolerance. For most use cases, the automatic setting is the best practice.

Map Topology Options
Caution:

Increasing the cluster tolerance can potentially reduce the spatial accuracy of your data and cause features to collapse or distort. This occurs as more feature elements are snapped together and determined to be coincident.

Geodatabase topology

Geodatabase topology defines relationships among features in the same feature class, different feature classes, or subtypes. For example, you can define a topology rule that specifies a coincident point feature must exist at all road highway intersections.

To learn more, see Create a topology.

Validating features participating in a topology rule symbolizes and records errors on a separate topology group layer. You can mark errors as exceptions or fix errors using predefined fixes or common editing tools.

To learn more, see Validate and fix geodatabase topology.

Contents pane geodatabase topology layers

Network topology

Network topology is exclusive to utility networks. It stores and manages information about the network and maintains connectivity among traversable and nontraversable features. Utility networks do not participate in map topology.

To learn more, see About network topology.

The owner of a utility network can enable or disable network topology. You can perform most editing operations whether it is enabled or disabled, such as create or edit features, feature templates, features, and associations.

To learn more, see Network topology actions .

When network topology is enabled, editing a network generates a symbolized buffer around the modified area on a sublayer named Dirty Areas. Validating topology incorporates your changes and removes the dirty area. If network topology is disabled, a single dirty area is created over the entire network.

To learn more, see Dirty areas in a utility network.

Contents pane network topology layers