Geography Reference
In-Depth Information
•
On-line tutorials, templates and 'wizards'
within map composition modules in ER-
Mapper and Erdas Imagine have also helped
to provide an element of guidance for the user
to (1) use the product and (2) produce a
reasonable map end product.
Dynamic maps, animation and virtual reality
Computer-based visualisation has recently
provided a number of new possibilities for
cartography that were previously somewhat
difficult to make use of despite widespread
recognition of their value. A number of authors
have discussed the value of animation in the
display and communication of spatial information
and changing patterns over time (e.g. Monmonier
1990; DiBiase
et al
. 1992; Dorling 1992; Peterson
1995, see also http://maps.unomaha.edu/books/
iacart/book.html; http://www.utexas.edu/depts/
grg/gcraft/notes/cartocom/section8.html;
MacEachren and Kraak 1997; Kraak 1998a). The
concept and practice of animation dates back to
the 1960s (Kraak 1998b; see also Campbell and
Egbert 1990), although obviously not in the
sophisticated form that it is today. While many
maps in use are typically of the static kind, there is
a clearly defined role for the animated map or the
use of animation techniques (both temporal and
non-temporal) to display, e.g., spatial changes over
time and sequences of maps (Kraak 1998a). Kraak
(ibid.)
provides a simple but effective example
showing the spatial growth over time of Enschede
in the Netherlands. DiBiase
et al
. (1992) outline a
project involving the design of animated maps for
a multimedia encyclopedia on CD-ROM (http:/
/www.deasy.psu.edu/deasy/mepaper.html).
Simple change detection over time can be
achieved using the 'swipe tools' within ERDAS
Imagine to alternate between a base map layer and
a current image layer (aerial photograph/ satellite
image). Similarly, a simple form of map animation
can be achieved using the slide-show tools in MS
Powerpoint.
Other more sophisticated examples are 'fly-bys'
through terrain generated by draping a map, aerial
photograph or satellite images over a digital
elevation model (DEM). Good examples of the
potential are provided in most digital image-
processing software, e.g. ERDAS Imagine, ER-
Mapper and PCI EasiPace, as demonstrations.
More than one layer can be draped over a terrain
model, e.g. the combination of a classified satellite
image, map vector data and place names. While
•
A map design tutorial on the Geographer's
Craft pages at the University of Texas at Austin
also provides guidance (http://
www.utexas.edu/depts/grg/gcraft/notes/
cartocom/cartocom_ftoc.html).
•
Journal papers (see Brown 1993).
Colour
Some attempts have been made to provide the
means to help users with colour choice in an
electronic medium. These have taken the form of
various academic research studies resulting in
paper-based colour reference charts, computer-
based colour tutors, and the use of artificial
intelligence (AI) in the form of knowledge-based
and expert systems (e.g. Gill and Trigg 1988; Brown
and Schokker 1989; Wang and Brown 1991;
Schettini
et al
. 1992; Brown and van Elzakker 1993).
DEVELOPMENTS IN COMPUTER-
BASED CARTOGRAPHY
Visualisation
The development of computer technology and
also GIS, together with growing use of spatial data
as a whole, has seen much greater emphasis placed
upon the use of the computer as a means of
visualising digital spatial data in a wide variety of
different ways, of which maps are but one form of
representing and examining spatial distributions
and patterns, trends and processes (Kraak and
Ormeling 1996; Kraak 1998b). While traditional
and computer-based visualisation techniques are
not new, the computer tools now available with
PCs offers even greater potential than before to
examine, explore, analyse and to display spatial data
(see http://www.itc.nl/~carto/showcase/
index.html).
