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When the project leader is acquiring data for the project, the 
data should be assessed for factors such as quality, cost, 
coverage, availability, information content, accessibility and 
product format. There are many sources of spatial data and 
there are several catalogues of data holdings. 
4.24 Training 
One of the often overlooked elements of a successful GIS 
implementation is the training. As mentioned, the project 
leader should receive general GIS training from a non- 
commercial organization. This should provide the project 
leader with an unbiased overview of the methodology and 
implementation of GIS. However, once the decision has been 
made on hardware, software and data, then vendor specific 
training must be taken. 
It is important also to evaluate the training available from the 
vendor when selecting the hardware, software and data. Some 
criteria for the evaluation of training packages include: cost, 
schedule, content, workbook/text and availability. Most 
vendors have an array of courses available for selection. 
4.2.5 Application Development 
In most cases the products that are on the market today have 
sufficient capability to perform most of the functions required 
by the system in an easy to use manner. However, there are 
cases where some customization is required. These may be for 
functions that are not available, the function is clumsy to use 
or a special database schema is required for the application. 
There are basically three approaches provided by a software 
vendor to extend the functionality of its software. One way is 
to provide a macro language, which is a procedural language 
that incorporates the normal commands that are used to 
operate the GIS. Another method is to provide a suite of 
callable object subroutine libraries that could be used to 
invoke the operations of a GIS. This method, unlike the first 
one, requires the use of a programming language compatible 
to the callable subroutines. A third method is to incorporate 
the GIS commands (normal or macro) in a programming 
language. The hybrid programming codes generated must first 
be processed by a pre-compiler supplied by the vendor to 
convert the GIS commands to subroutine calls. 
In most cases the project leader of a desktop GIS project is an 
application specialist such as a forester, environmentalist or 
geologist. Most are not GIS specialists or computer 
programmers. In order to effect the modifications it is often 
most expedient to contract for custom program development to 
à competent company. If the system is being developed as a 
pilot project for a potentially larger system, then it is essential 
that a GIS consultant be contacted. This consultant may be 
able to provide a long term vision for the project. 
309 
5. Summary 
It is clear that the computerization of geo-processing tasks will 
continue into the foreseeable future. With the announcement 
of Windows-95, the computer revolution is continuing to grow 
in momentum. The performance gap between PCs and Unix 
workstations is basically non-existent and users will need to 
make their system decisions based on price, reliability, 
upgradeability and so on. With the advent of a widely used 
32-bit operating system for PCs, very sophisticated GIS 
applications can be developed. 
The desktop GIS project manager will have potentially more 
decisions to make in the future, but these decisions should be 
easier to make and the technology should provide a more cost 
effective and robust solution. This ever improving technology 
will advance the way people use computers and will ease the 
development of novel desktop GIS applications. 
6. Bibliography 
Plunkett, Gordon and Lee, Y.C.; Factors in the Development 
of a Desktop GIS; Proceedings of The Canadian Conference 
on Geomatics, June 1995, Ottawa. 
Gunston, Mike; Geographic Information Systems: A Buyers 
Guide; ISBN 0 11 330606 7; CCTA, London, 1993. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996