ESTABLISHING SPATIAL RELATIONSHIPS

All features that should have been digitized, really are (no missing data).
All features that are there, should be there (No extra data)
The features are in the right place and the arcs have the correct shape (data is accurate)
Features that should connect, actually do
All polygons have one, and only one, label point
All features are within the outer boundary

BASIC STEPS IN CREATION OF TOPOLOGY AND CORRECTION OF ERRORS

Complete digitizing of features
Construct topology
Identify errors
Reconstruct topology
Add attribute information

CONSTRUCTING TOPOLOGY

Identifies arcs that do not connect to other arcs
Polygons that are not closed
Polygons that have no label point or too many label points
Incorrect user id's

IDENTIFY DIGITIZING ERRORS

four basic types:
Extra arcs
Missing arcs
Dangling nodes
Pseudo nodes
Missing labels
Extra labels

The first two require manual identification by plotting and overlaying digitized maps with the original manuscript.

The second two can be automatically identified by using the NODEERRORS command in ARC or by using ARCEDIT to locate the DANGLES or PSEUDO nodes.

The last two can be identified using the LABELERRORS command in ARC

WHAT COMMAND BUILDS TOPOLOGY IN ARC

The CLEAN command identifies intersecting arcs with no nodes, identifies dangles and pseudonodes. It can be used to eliminate dangles and undershoots during the digitizing process. After correcting for errors it will build topology

The build commands assumes that there are no errors of intersectiong arcs without nodes and simply builds the TOPOLOGICAL RELATIONSHIPS

CLEAN should be used sparingly and only if you have added arcs that may intersect without nodes. Use the INTERSECTERR command to identify intersects.

After adding label points, or deleting unwanted arcs, or if you add arcs and make sure that all intersects are accounted for, use BUILD. If there is an intersect error it will bail out and then you should use clean.