Carto 2005: Cartographic Preview of ArcGIS 9.2
Published Wednesday, July 27, 2005 by CCAer | E-mail this post
Edie Punt of ESRI
provided a preview of some of the cartographic enhancements being made in ArcGIS 9.2, currently in pre-beta development and scheduled to be released in early 2006. The focus of the enhancements centres on the use of representations, a more advanced form of the currently existing layers feature in ArcGIS.
Representations are meant to be used in high-end cartographic products and offer the user flexibility and consistency in how their data is symbolized, similar to layers. What is news is that representations are rule-based and are stored inside the geodatabase. These rules can be overridden; indeed, individual features can be selected on the map and symbolized differently than the other features in the same category. As well, an alternate geometry can be created specifically for mapping purposes and stored without impacting the spatial integrity of the underlying data. Symbology can be manually altered for specific cases, for example, adjusting the positioning of dashes on a line. In fact, features can be treated much like graphics in a graphics program: they can be sized, rotated, shaped and symbolized individually all without affecting the underlying database. Those familiar with Adobe Illustrator will recognize many of the tools and features that 9.2 will have to offer.
A representation is made up of two parts: a symbol layer and a geometric effect. A symbol layer can be one of three types - fill, stroke or marker. Multiple symbol layers can be used to represent a data layer. A geometric effect dynamically processes geometry before it is drawn. This includes such things as simplifying a line. Geometric effects can work on all symbol layers or just one and can work sequentially. Lines can be made to appear simplified or offset from their original position, all without affecting the underlying database.
All of the properties of a representation are mapped to a specific field and the resulting field acts as a lookup table. Another field can track manual overrides. As a result, the data ends up driving the symbology while still allowing the user to retain control over the appearance of all the features.