FAQ: Can I edit coverages in ArcMap at version 8.3 and 9.0?


Can I edit coverages in ArcMap at version 8.3 and 9.0?


Direct editing of coverages in ArcMap isn't supported in ArcGIS 8.3.

The following excerpt from "What is ArcGIS?" for Version 8.3, page 76, explains why coverage editing is no longer supported from within ArcMap:

"In ArcInfo Workstation, the coverage data model has strict topology rules and mechanisms to maintain topological integrity. These are based on the use of topological pointers - internal feature IDs (often referred to as the cover#) - for each feature class in the coverage. ArcEdit is the application that works closely with commands, such as BUILD, CLEAN, and RENODE, to maintain this strict topological data and internal ID structure. Topological editing, not simple feature editing (such as shapefile editing), is the focus in ArcEdit. Thus, data must always be edited as coverages in ArcEdit.

In ArcGIS, the fundamental method for managing a feature class is based on the OGC and ISO simple features specifications: a feature class is managed as a standard DBMS table where each row holds all information for a single feature. One of the columns holds the geometry (that is, shape) of the feature. This enables ArcMap editing to work with many multipurpose, open data models, such as shapefiles and feature classes from any geodatabase (personal and multiuser). While ArcGIS can use and consume coverages effectively, it cannot edit coverages with any degree of consistency. Thus, coverage editing is not supported in ArcGIS 8.3.

ArcInfo Workstation focuses on coverage editing with latent support for editing some additional data types. ArcEdit is built around the coverage's topological data model and maintaining its integrity (internal cover # IDs, arc-node lists, polygon-arc lists and so on).

Editing in ArcMap is based on the OGC/ISO simple feature data model (complete feature geometry in simple, standard tables) and includes a comprehensive topological editor that implements the specific user-defined topology rules for each dataset. Thus, ArcMap is not a coverage editing environment but works well for most open vector data models that adhere to standards. This includes the editing of shapefiles and feature classes in any geodatabase."

The full copy of this resource, "What is ArcGIS?" is available online by clicking on the ESRI White Papers link, below. Continue by clicking ArcInfo Workstation > What is ArcGIS?-December 9, 2002. This is a PDF and requires Adobe Acrobat.

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