Because there were some undershoot dangle errors with gaps larger than three feet there are some lots that were not completely enclosed. Where the gap opened onto an adjacent lot, and the two lots’ other boundaries were closed, a single large lot was created. In this example you’ll see how to split up one such lot.

There appear to be two lots on either side of a Must Be Covered By Boundary Of line error. In fact, selecting one of them reveals that they are a single feature. The Line error marks a lot polygon boundary that was not constructed.

The point error at the south end of the line error is an undershoot dangle error. You’ll see a new method to fix this error using a tool on the Advanced Editing toolbar.

The Extend tool works differently from the Extend topology error fix. Rather than specifying a distance, you select a feature to which the tool will extend a line. After a feature is selected, you click the line feature that you want to extend. Since the parcel is currently selected, all you have to do is click the dangling lot line. You’ll zoom in a little closer to see the gap.

With the Extend tool, when the pointer gets close to the endpoint, the blue circle snaps to it. Although you can click anywhere on the line that you want to extend, the Extend tool obeys the current snapping environment. Since you set up snapping to endpoints of LotLines earlier, the Extend tool snaps to them.

When you click the line it is extended to the nearest selected feature—in this case, the edge of the Lot polygon.

The Selection tab of the table of contents makes it easier to quickly specify which layers are selectable. In this example you want to select only the line feature. Click the line that you just extended, and make sure it is the only feature that is selected.

The Construct Features tool has an option to split existing features in the target layer using a selected feature. Using this option with the newly extended line feature splits the existing parcel into two features.

When the topology is validated the line error and dangle error are removed.

You will need to check the attributes of both of these lots against the attributes of the LotIds points and update one or both of them to make sure that they have the right PARCEL_ID numbers. The new lot feature has a null PARCEL_ID, and there is a 50 percent chance that the wrong parcel inherited the value from the original large parcel.

There are many more errors in the data, although as you saw in this and the previous examples, more than one error may be related to a given problem. Almost all of the errors follow from the underlying problem of the original CAD data, incompletely snapped line work, and unclosed polygons. Spending more time editing the dangle errors would have taken care of most of the errors that were revealed by adding the new rules.

Some of the errors, like the small dangling line and the lot line not covered by a parcel boundary visible here, may not need to be corrected at all. If your organization needs only to model lots, the LotLine and LotIDs feature classes could be removed from the topology and deleted once you’ve finished developing the polygon features from them. On the other hand, you might want to keep the lot lines for cartographic reasons or to simplify annotating the dimensions of lots. If this is the case, you would need to continue cleaning up the lot lines. An additional step would be to use the Planarize Lines tool to split all of the lot lines at intersections—something that was not done with the original CAD data. The two errors visible above are actually on the same feature. Planarizing the lines would split this feature into several features, each tracing a single lot boundary.

Whether or not you retain the LotLines and LotIds feature classes, you would probably want to add at least one more rule to assist in the day-to-day management of the lot feature class. One such rule would be a Must Not Overlap rule, so when you digitize new lots they cannot overlap each other. This should not be a problem for the lots you’ve just created, but it is a rule that one would typically enforce on landownership polygons.

In this example you saw how to create a geodatabase topology with simple rules to help you clean up data. You learned how to use the Error Inspector to find errors of a particular type and how to use some of the many editing tools to fix errors in your data.