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ArcInfo 8 Embodies Modern GIS Theory So GIS Can Use DBMS Technology for Managing Data

Introducing the Geodatabase

ArcInfo 8 makes sophisticated GIS easier to use and incorporates the latest concepts of GIS theory. The Summer 1999 issue of ArcNews included a special eight-page section that specified the features of ArcInfo 8 and introduced three new applications. ArcMap is the map-centric application for editing, displaying, querying, and analyzing map data. ArcCatalog is the data-centric application that locates, browses, and manages spatial data. ArcToolbox is the environment for performing geoprocessing operations.

The geodatabase allows distributed GIS data management in any DBMSJust as significant as these three new ArcInfo 8 applications is the newly introduced object-oriented data model called the geodatabase model--which is added to the existing georelational model (i.e., coverages and shapefiles with attributes) and increases data model flexibility.

The chief purpose of this new object-oriented data model is to make it easier and more intuitive to use ArcInfo across many application areas. The geodatabase model achieves this by letting you add intelligence to features in your data sets in the form of behavior, properties, and relationships. In addition to generic features, such as points, lines, and areas, you can create features that more closely resemble the real world such as parcels, buildings, and transformers.

According to Bob Parlock, the director of engineering products development for Telecordia Technologies, Inc., "The new object-oriented data model is superior to the old in that we can work directly with actual domain objects rather than just simple rows in a table."

A geodatabase is a physical store of geographical information inside a relational database. You can implement multiuser geodatabases or single user, personal geodatabases. A personal geodatabase is stored in Microsoft Jet Engine (the format used by Microsoft Access). Available as an ArcInfo 8 extension, ArcSDE 8 can manage large sets of geographic data and serve large numbers of viewers and editors. ArcSDE allows ArcInfo to manage geodatabases on a variety of database platforms including Oracle, Microsoft SQL Server, Sybase, and Informix.

In ArcInfo 8, you can view, manage, and create geodatabases with ArcCatalog and map and edit them with ArcMap. ArcToolbox also contains tools for converting other data formats to geodatabases.

Some of the benefits of the geodatabase data model are

  • A uniform repository of geographic data--All of your geographic data can be stored and centrally managed in one database.
  • Data entry and editing is more accurate--Fewer mistakes are made because most of them can be prevented by intelligent validation behavior. For many users, this alone is a compelling reason to adopt the geodatabase data model.
  • Users work with more intuitive data objects--Properly designed, a geodatabase contains data objects that correspond to the user's model of data. Instead of generic points, lines, and areas, the user works with their transformer, road, and lake objects.
  • Features have a richer context--With topological associations, spatial representation, and general relationships, you define not only a feature's qualities, but also its context with other features. This lets you specify what happens to features when a related feature is moved, changed, or deleted. This context also lets you locate and inspect a feature that is related to another.
  • Better maps can be made--You have more control over how features are drawn, and you can add intelligent drawing behavior. You can apply sophisticated drawing methods directly in ArcInfo 8 software's new mapping application, ArcMap. Highly specialized drawing methods can be executed through writing software code.
  • Features on a map display are dynamic--Features in ArcInfo can respond to changes in neighboring features. You can associate custom queries or analytic tools with features.
  • Shapes of features are better defined--The geodatabase data model lets you define the shapes of features using straight lines, circular curves, elliptical curves, and Bezier splines.
  • Sets of features are continuous--By their design, geodatabases can accommodate very large sets of features without tiles or other spatial partitions.
  • Many users can edit geographic data simultaneously--The new geodatabase data model supports work flows where many people can edit features in a local area and then reconcile any differences that emerge.
  • Users can edit data with the security of a long transaction--If the database goes down, all edits are not lost.

"ArcInfo 8 continues to support all existing Esri file formats and adds the new geodatabase format," says David Maguire, Esri director of product planning. "Users can keep their data as coverages or use the new geodatabase format if they want to take advantage of its advanced capabilities."

You can learn more about ArcInfo 8 and the geodatabase by signing up for the free Virtual Campus course titled Introducing ArcInfo 8 at Esri Training and Education. ArcInfo 8 will soon be available and supports Windows NT and UNIX platforms. For more information on ArcInfo 8, please visit Esri online at www.esri.com/arcinfo, or contact Esri at 1-800-447-9778. Outside the United States, please contact your local Esri distributor.

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