CONFIGURING A PC TO RUN ARCVIEW 2.1

INTRODUCTION

As the need for desktop GIS increases, a software product like Arcview can 
become an integral part of a business’ way of life. In the GIS community, 
it is common knowledge that Arcview can allow anyone, with basic Microsoft 
Windows knowledge, to create maps and query data tabularly and spatially 
with a minimum amount of training. 

As with any software package, the data is what makes it a powerful and 
useful tool. GIS data can come in many different formats, ranging from 
index cards and file folders to rectified aerial photographs. The focus 
of this paper is to demonstrate how data is organized, how data is 
accessed and which platform to choose to get the most out of 
Arcview 2.1.

THE PHYSICAL CONNECTION

The City of Las Vegas has an Ethernet network spanning the 10 story 
City Hall building. At a rated speed of 10 Mbits per second, 
Ethernet provides good speeds for transfer of the typically large 
GIS data sets. It is very important that the network administrator 
constantly tune the network so that optimal performance can be 
achieved the majority of the time the network is being used. Extremely 
heavy network traffic will cause Ethernet networks to retransmit data 
packets which can significantly degrade network performance. Typical 
costs for Ethernet cards are about $100 for ISA cards (IBM 
compatibles), $160 for PCI cards (Macintosh and IBM compatibles) and 
$150 for NuBus cards (Macintosh). Ethernet is a built-in feature 
on Sun Sparcstations.

If at all possible, faster networks are highly desirable. Fast 
Ethernet and FDDI, both of which are rated at 100 Mbits per 
second, offer real world data transfer times of three to four times 
that of normal Ethernet.

THE COMPUTER

The choice of microcomputer and its options is one of the most 
important choices to make when putting together an Arcview 2.1 
capable machine. At the City of Las Vegas, the standard 
recommendation for an Arcview machine is a Pentium 120 MHz or 
faster, 32 Mbytes of RAM or more, 512 Mbytes of disk storage space 
and a 17 inch color monitor or larger. A PC equipped with these 
options range from $2500 to $3000.

If Arcview 2.1 is to be run on a Sun SparcStation, a SS 20 is 
highly recommended. Multiple processors will significantly improve 
performance. A typical SS configuration for a single user might 
be 128 Mbytes of RAM, 1 Gbytes of disk storage space and a 17 
inch color monitor or larger. A single processor system equipped 
with these options could cost about $15,000.

On certain operations, such as table joins and data reselects, 
a 75 MHz Sun SparcStation can be two to three times faster 
than a 120 MHz Pentium machine. UNIX workstations are designed 
from the bottom up for speed.

THE OPERATING SYSTEM

The choice of operating systems is just as important as the 
choice of computer. While many users have had success running 
Arcview 2.1 under Windows 3.1 and 3.11, those users at the City 
of Las Vegas running Arcview 2.1 under Windows NT or Solaris 
have had better overall performance and fewer software related 
problems. Both Windows NT and Solaris are true 32-bit pre-emptive 
multi-tasking and multi-threaded operating systems. 

DOS, upon which Microsoft Windows is built, is a single user 
16-bit operating system. Many of the problems encountered using 
Arcview 2.1 while running Windows 3.1 can be attributed to 
DOS’s limited memory handling capabilities. Even in enhanced 
mode, many of the Windows 3.1 resources are located in memory 
below the 640 Kbyte memory barrier. Those limitations do not 
exist under Windows NT and Solaris. 

Due to Windows NT and Solaris’ ability to multi-task, an Arcview 
process that may take 20 minutes can run in the background while 
the user reads his e-mail or types a letter in his word 
processor. Under Windows 3.1, Arcview cannot be placed in the 
background to run. The machine is effectively held "captive" 
until the process completes. This is a significant time saver 
when dealing with large data sets.

FILE SHARING SERVICES

Since most GIS data sets are created on non-PC platforms (VMS, 
UNIX, etc.), one has to find a way to allow the Arcview 
application on the PC to read the GIS data on a foreign platform. 
At the City of Las Vegas, GIS data sets are created and 
maintained using Arc/Info on Sun Sparcstations running 
UNIX (Solaris).

The easiest way to give the Windows NT workstation access to 
the UNIX disk partitions is to install NFS client software on 
the Windows NT workstation. The City of Las Vegas uses 
Intergraph’s PC-NFS for Windows NT, but similar products 
are made by Hummingbird Communications, Beam and Whiteside 
and FTP Software. These products allows a Windows NT client 
to mount a UNIX partition using the Windows file manager. To 
a Windows user, this is the same process as mounting a 
Netware or LAN Manager volume. The cost of NFS client software 
for Windows NT averages $500 per user (single license). Multiple 
license packs can reduce costs substantially.

Those shops who have committed to Novell Netware as their NOS, 
can purchase Novell’s NFS gateway. This is an NLM that mounts 
a UNIX partition and makes it available (looking like a Netware 
volume) to the Netware users logged into that server. The City 
purchased a 25 user version for about $2500. Performance is 
compromised because all data must travel from the UNIX partition 
through the file server before arriving at the workstation. 
This can be very inefficient. Also, a shadow file (pointers 
to UNIX files) exists on the Netware server for all files on 
the UNIX partition. This wastes additional file server disk space.

ORGANIZING DATA

Coverages should conform to DOS’ 8.3 naming convention as to avoid 
the NFS software trying to interpret character names longer than 8 
characters. Generally speaking, the interpretation is wrong. Large 
data sets should be stored in Arc/Info map libraries. The City has 
yet to experiment with ArcStorm, therefore no performance comparisons 
are not available. Arcview 2.1’s area of interest feature allows 
Arcview to focus on a single (or a few) map library tiles to speed 
up query and redraw times. When operations are performed on the 
entire map library, performance suffers greatly.

Directories should be named and coverages should be stored so 
associated data sets are in the same directory whenever possible. 
Each directory should contain fewer than 50 coverages. Otherwise, 
when adding themes to a project, the time required to scan the 
directory will be substantial. Although not much of an issue now, 
coverages should be stored in an Arc/Info 7.x coverage format. 
Arcview can read version 6.x coverages only under certain 
limited circumstances. A 7.x coverage can be read under 
most circumstance.

Shape files are Arcview’s native data format. These file can be easily 
edited and changed by Arcview and the tabular data is stored in the 
industry standard DBF file format. Shape files are a great way to 
make subsets of large GIS data sets for use with Arcview projects.