[OSGeo-Discuss] Re: Comparision between MapServer/OpenLayers and ESRI ArcIMS

[Julia Harrell]

Hi Bill

In addition to the excellent advice others have already given you, be sure to consider the extra hardware infrastructure that will be necessary to support this much 3D data, on-the-fly geoprocessing, and large numbers of concurrent users. If your client chooses an ESRI solution, it will take a lot more than they probably counted on purchasing to get a system that will perform adequately. ArcGIS Server is a real resource hog. Check out Dave Peter's new "Building a GIS" book. Not that I am a fan of the AGS software at all, but Dave is a really smart guy and he's put a huge amount of work into designing and fine tuning his "Capacity Planning Tool", which is now available. One used to have to go take the ESRI System Design Class in order to get a copy of the tool. I took it a couple years ago from Dave, and can attest to his thoroughness in building the CPT. You can download updated versions of the CPT from the website now. 

http://gis.esri.com/esripress/display/index.cfm?fuseaction=display&websiteID=141&moduleID=42

The CPT is pretty complex and does take some training to use properly, so unless you're going to take the system design class, you probably ought to get the book. It would be great if, one day, a similar tool was available for Mapserver/Geoserver/PostGIS systems (hint, hint listserv experts). Unfortunately, I'm just not knowledgeable enough about the inner guts of the OpenGIS softwares yet to be able to convert all the formulas in Dave's spreadsheet to something more appropriate for an OpenGIS system.

I was a little surprised to see just how *much* server hardware and network bandwidth it would *really* take to implement a usable ESRI server-based GIS system for my organization, which has offices all over the state and crappy bandwidth in a lot of the more remote places, not to mention the uncountable anonymous public users. Right now we've got AGS running on a single server, and it is dog slow and needs a lot of babying. When I told my "IT overlords" that I'd need at least 2 more load balanced GIS processing servers and a separate production GIS database server to speed things up to an acceptable level, well, they just laughed at me. Mapserver, PostGIS and Geoserver all run "OK, but not blazingly fast" on a single, older shared GIS server for me. AGS gets the other, newer GIS server all to itself - and is still a complete pig. Sure, the OpenGIS software would be a lot faster if they each had their own dedicated box, but in this budget climate, extra funding for more hardware is just not possible...

Hope this helps,

Julia Harrell