GRASS
was chosen to be
the GIS because it is a public--domain package that is available on
many workstation environments. The user may already have map layers in
the GRASS format or can readily convert maps from other popular
packages such as ARC/INFO to a GRASS format. Since the
output maps of LUCAS are also in a GRASS format, the user can take
advantage of the rich utilities that GRASS has to offer for further
analysis. GRASS also was easy to integrate into LUCAS because it
offers a series of map manipulation libraries with all of their source
code and a well--defined programming interface [12]. The use
of GRASS as the source and sink of map manipulation in LUCAS is
illustrated in Figure 3.
GRASS is not a perfect tool, however. As a non-commercial package, many bugs persist in the code. For example, the GRASS X-windows monitor often functions properly under SunOS 4.1.3, but not under Solaris 2.4. Some of the features of GRASS are not well documented, which made the availability of the source code invaluable. The environment works well for someone with knowledge of UNIX and programming, but would be rather challenging for an ecologist without such skills. In spite of its many foibles, GRASS is a useful environment in which to work and program.
Figure 3: Use of GRASS (GIS) as the source and sink of map manipulations
in LUCAS.