Does topology validation move features automatically or does it require me to make fixes?
When validating Geodatabase Topology, areas that violate the rules established for the topology result in flagged errors that need to be fixed. This is the portion of the data that is not changed; the user must make the changes.
However, if features or vertices are closer together than the cluster tolerance distance (ArcGIS Desktop 9.3 Help: Determining cluster tolerance), they will be 'cracked and clustered' (adjusted) to become one feature or to be made coincident during validation. This is the portion of the data that is changed automatically.
For example, if a rule is defined on a parcel feature class so that it 'Must Not Have Gaps,' and there is a sliver of open space between two parcels, the width of the gap and the size of the cluster tolerance determine if the error is fixed automatically during validation, or if there is an error logged that must be addressed manually.
If the cluster tolerance is 1 foot, for example, and the sliver is only 6 inches wide, this error is automatically fixed, and the two boundaries are cracked and clustered (reorganized) during validation. This can be a great help when there are thousands of very small editing errors. If the gap is larger than the cluster tolerance, such as 2 feet in this instance, then the error is flagged and the user will have to fix the error manually.
Manual inspection and fixing can be assisted by the Error Inspector
window and the Fix Topology Error
tool in the Topology toolbar. In many cases, selecting a record in the Error Inspector window (or clicking the visual representation of the error in the map with the Fix Topology Error tool) allows a selection to be made from available repair options and directs ArcMap to perform that repair on the selected error.