Review: ArcGIS combines three modules into one powerful product
Since we last tested geographic information system solutions in September 2000, ESRI has undertaken a complete makeover of its GIS product line. With the power of a computer-aided design tool, ArcInfo is still available as a separate product, as is the simplified Microsoft Corp. Windows-based ArcView. But now ESRI has combined the best of both into a new suite: ArcGIS.
ArcGIS comprises three modules: ArcMap, ArcToolbox and ArcCatalog.
For most users, home base will generally be ArcMap. Like ArcView, ArcMap is designed from the bottom up as a Windows application for map editing, querying and displaying. We found ArcMap, however, not only more powerful but easier to use than ArcView. Toolbars are intelligently designed and organized, and they can easily be dragged to a desired location in the main ArcMap window or anywhere else on your Windows desktop.
Querying map data and displaying thematic maps — such as proportional or dot-density fills representing ranges of data — are not quite as easy with ArcMap as they are with MapInfo, but one quickly gets used to the procedures. And we were very impressed with the tools for managing attribute tables, including the ability to rearrange and freeze columns and to join and relate data with data in other tables.
We also found it easier to use ArcMap for map creation and editing than most other programs. For starters, we especially liked the fact that all layers in a map are selectable and editable by default. In other words, you don't have to first make a specific layer editable before you can select and change a feature on that layer, as MapInfo requires. We were also impressed with the array of editing tools provided, including object rotation, which is important in computer-aided design.
Unlike most desktop mapping programs, ArcMap enables you to create objects of virtually unlimited complexity. Nearly all of the data-creation capabilities of the ArcInfo product are available either directly or by calling up the second module of the suite, ArcToolbox.
ArcToolbox allows you to perform geoprocessing and conversion chores — such as changing the projection of a batch of data files or performing calculations on map data — from a centralized location and without having to individually load files. The broad array of tools provided — which will be familiar to users of ArcInfo — may seem daunting at first, but you can quickly assemble your own collection of frequently used tools to keep close at hand.
Assuming your systems administrator has set things up properly, you can even send projects off to a remote Geoprocessing Server to be processed, thus freeing up local resources. And datasets can be managed on the network in a manner that will allow multiple editors to work with files without conflicts.
The third primary module — ArcCatalog — allows users to browse and manage data files without having to actually load them into ArcMap. The simple interface makes it easy to create or edit metadata, or to change attributes in files. What's more, if you want to open a file, you can simply drag and drop it into ArcMap.
ArcGIS' support for enterprise databases and data file formats is also unsurpassed.
Finally, ArcGIS earns high marks for programmability. Unlike most GIS solutions, ArcGIS has an open architecture comprising more than 1,100 components that can be employed using the built-in Microsoft Visual Basic for Applications scripting or programming languages such as Visual Basic or Visual C++.
ESRI's solution for publishing interactive maps on the Web is ArcIMS. ArcIMS is complex and takes time to employ, but it is also more flexible and powerful than the other solutions we tested.
You can't, alas, simply convert a map created in ArcMap for use in ArcIMS. Instead, you must first create a new map "service" using ArcIMS Manager, then add the various shape and data files that will be employed. At the same time, you can specify layer properties, such as symbols that will be used and the order in which layers will be drawn.
ArcIMS offers two types of map services. Image Virtual Server is the best choice if your map application is strictly HTML and will only involve viewing and simple queries. If your application will be more complex and involve interaction and analysis by users, you want the Java-based Feature Virtual Service.
Once you have selected a map service and specified the data to be included, all you need to do is choose a viewer and select interface elements. ArcIMS lets you specify either an HTML viewer or a Java viewer, and the program gives a good deal of control over placement and content of toolbars and other aspects of appearance.
We were also impressed with ArcIMS' scalability. The program offers good tools for tracking numbers of users and response times of the map servers. If performance drags, you can first increase the use of virtual servers then install ArcIMS Spatial Server on another computer and enable load balancing, or both.
Make no mistake, ArcGIS and ArcIMS are not simple programs to learn, particularly for map creators and editors. But the ESRI suite offers tools and capabilities that can't be found in desktop GIS programs. At the same time, we found that ArcGIS and ArcIMS were much easier to use than other enterprise-level solutions, including Intergraph Corp.'s GeoMedia.
If there is a downside to ArcGIS — other than its high price tag — it is the very profusion of tools it offers for map creation and analysis. If you can't dedicate the staff resources to learning and employing ArcGIS and ArcIMS, you'll be glad to know that the programs are backed by an extensive community of developers and consultants.
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