ArcGIS™: Working With Geodatabase Topology
® An ESRI White Paper • May 2003
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J-9037
ArcGIS: Working With Geodatabase Topology
An ESRI White Paper
Contents Page
Overview ...... 1 Introduction ...... 1 How Is Topology Used?...... 2 Setting Topology Rules...... 2 Data Models and Topology...... 3
Understanding How It Works ...... 4 The Basics ...... 4 Cluster Tolerance ...... 5 Ranks...... 5 Topology Rules ...... 5 Dirty Areas ...... 7 The Validate Topology Command ...... 7 Validate Topology Versus BUILD...... 8 Errors and Exceptions ...... 8 Shared Geometry...... 10
Coverage Model Versus Geodatabase Model ...... 11
Working With Topology ...... 12 Converting Coverage Data to Geodatabase Feature Classes ...... 12 Building a Topology...... 13 Topology Wizard in ArcGIS...... 13 Editing a Topology...... 18
Summary ...... 19
ESRI White Paper i
J-9037
ArcGIS: Working With Geodatabase Topology
Overview Topology—the spatial relationship between geographic features—is fundamental to ensuring data quality. Topology enables advanced spatial analysis and plays a fundamental role in ensuring the quality of a geographic information system (GIS) database. In the ArcInfo™ coverage model, hundreds of thousands of GIS users worldwide learned the benefits of topology by performing the build and clean operations on their databases. ESRI® ArcGIS™ 8.3 introduces a new suite of editing tools necessary to construct and maintain user-defined topological relationships within a geodatabase. In ArcGIS, the Validate Topology capability will ensure data integrity by validating the features of a geodatabase against a set of topology rules.
One of the primary objectives of the ArcGIS 8.3 release is to add full topology to the geodatabase. Until the ArcGIS 8.3 release, topology was a feature of the ArcInfo coverage data model. The introduction of the ArcGIS geodatabase provides an opportunity to expand what topology means for GIS users as well as its possible uses in modeling spatial data. Geodatabase topology is supported in ArcEditor™ 8.3 and ArcInfo 8.3.
Introduction So what is really meant by topology, and why is it important in the maintenance of a geographic database in ArcGIS?
The word topology has several meanings when discussed in the GIS context. It can refer to a