System Architecture Design for GIS
New Users
Every organization strives to find ways to trim costs and improve the bottom line. Reliant
Energy management recently approached the System Administration staff with some ideas about
using remote users to complete some gas service line piecework. A solution was needed to
support connectivity between users around Texas, and possibly using digitizer contract sources
from India. The present GIS environment was using VPN software to remotely connect users
working from home. A cool solution might connect remote India VPN users over the Internet,
using the Citrix client, and publish special Houston-based applications for their use. This would
allow GIS operations to take advantage of a less expensive labor pool. As of December 2001,
over ten clients are connecting from India to Houston using this remote connection solution.
Most of these clients are part-timers trained to use GIS software. These users enter gas services
into the Reliant system. Other clients are posting streetlights. Shared drives have been
configured on one of the Houston servers, where remote Internet clients leave screen prints of
their work. QA/QC people check the work before reconciling the remote user versions with the
default database and posting the changes. Remote users are required to run personal firewalls
and maintain commercial anti-virus software on their Citrix client desktop.
Citrix Nfuse Desktop
The Windows 2000 Citrix Nfuse environment is currently used to support production operations.
All of our production applications are available in this environment. Nfuse will simplify
maintenance by supporting deployment of required Citrix client software to the users. Nfuse
also removes the Support Desk administrative task of having to “walk” the user through client
software installations and configuration support for custom parts of the client, such as connection
information to new servers. Also, all client applications can be published on an existing GIS
Web server simplifying the look and feel to the end users. The Nfuse icons can embed within
the pages currently provided on the Web server, which once again simplifies administration.
Applications can run within the frame of the Web page or as standalone seamless windows.
Printing
The biggest issue encountered with the Citrix software is in the printing arena. Some printers are
not supported, and others have different standards in defining print-driver definitions causing
major difficulties. If a user tries to print to a printer that is not defined correctly, the Citrix server
can crash. GIS users hate to lose their work and don’t mind letting folks know about it. Printing
solutions were deployed using aliases and other configuration tricks suggested by Citrix.
Unfortunately, the Reliant environment today has a wide variety of printers and drivers. Unless
each specific driver is defined properly, the Citrix server will have problems. Users have been
advised not to use printers that were not compatible when printing from ArcMap via Citrix.
Some early tests on Win2000 and Citrix XP indicate that some of these problems are solved with
the next major release of the Citrix MetaFrame software. The Citrix XP universal print driver,
however, only supports black and white at 300 dpi, and that is certainly not good enough for a
GIS environment which requires support for large format to 8˝” x 11”, both black and white,
and color.
Third-party software from various vendors promise to provide a much more stable environment.
These alternatives will be tested to validate the best printing solutions. A stable printing
environment will easily justify the additional software cost. The printing problem really goes
beyond the crashed server. When a server crashes, the Support Desk has to get involved to help
identify exactly which user caused the crash while trying to print. Stranded connections might
have to be cleaned up. The users, of course, lose all work since the last save. System
Administration gets involved to actually fix the print driver problem. Finally, the users are
happy again—until the next system crash. Third-party print drivers promise to fix this problem.
A Few Other Issues
The GIS environment must include a test environment to support validation of a combination of
commercial off-the-shelf (COTS) software and software written in-house. Each of these
software releases must also be tested in the Citrix environment. The Citrix environment must
provide a user experience that exactly mimics the GIS software running on user’s desktop.
Problems in the past included lack of true-color support, transparent colors, different colors on
Citrix versus standard desktops, and other related issues that have caused confusion to the users.
The test platform is sometimes involved in other types of tests and not available for Citrix
testing. A very simple test alternative has been to take one server out of the Citrix production
farm, install the upgraded software, and have a few users production test the software to iron out
any Citrix-induced kinks that may arise.
