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 ArcInfo 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 ArcInfo 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 ArcInfo 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.