Helpful hints when using topologies

This topic applies to ArcEditor and ArcInfo only.

The following tips can help you when using geodatabase topologies.

Testing your proposed topology design

Use a file or personal geodatabase with a copy of your feature class data to try out your topology design. A copy is important because you will want to try to validate against your real data and see if your topology design works well. Validate will cluster coordinates and make changes to your underlying geometry. Some initial designs may not work as you expect. You will want to ensure that you have a copy of your original data before you test.

If you have an ArcSDE geodatabase used by many in your organization, be aware that you have less flexibility to change the schema without taking your system offline for the changes. Also, if you have a versioned geodatabase, you'll need to compress your versions before you apply schema changes. You can minimize issues with your workflows by good initial testing of your topology design with file and personal geodatabases.

Also, you can save your topology rules and definitions for reuse later in other geodatabase schemas.

During your tests

Work with your data to ensure that your design makes sense. For example, you should create the proposed rules, validate your topology, and use the ArcMap editing environment to find and fix a number of example errors discovered during validation.

Try alternative rules. Work to develop a better understanding of how the topology rules will best function in your specific situation.

Once you settle on a design, you can subsequently test it as part of your production schema.

Schema locking

An exclusive lock is required on all the input feature classes when building a topology. If any of the input feature classes has a shared lock, the topology will not be built.

If any of the feature classes in a topology have a shared or exclusive lock, that lock is propagated to all the other feature classes in the topology.

Learn more about exclusive locks and schema locking

Topology errors

It's important to realize that topology errors are discovered and recorded as features when you validate your topology.

For example, polygon-on-polygon areas are often reported as polygons or lines that show the errors. Line and point feature areas typically are recorded as lines and points.

You can view these as layers in ArcMap and zero in on each issue to correct it.

Published 6/8/2010