analyse spatial data is the key element in its definition. This is
the characteristic by which GIS differs from the systems having
the production of maps as their primary goal.
One of the most important procedures in using and applying
GIS and digital cartography is the visualisation of spatial data
(Figure 2). GIS enables an overview of changeable spatial data.
Maps make an addition insight into the essential issues possible
and supplement the research of data tables. Similar to statistical
graphs that can be used for making sense of large table data
quantities, digital cartography helps in interpreting large,
spatially determined data sets. GIS can be useful for education,
climate mapping, spatial analysis, demography, environmental
mapping, health, local government, regional mapping, tourism
or world mapping.
SYNTHESIS
E
APPLICATIONS |
Ts
«qp
CONTROL
ANALYSIS
GIS
‘
VISUALISATIONS
Figure 2. Possibilities of GIS
4. CARTOGRAPHIC VISUALISATION
Modern cartographic visualisation, according to Taylor (1994),
encompasses digital cartography and computer graphics.
Considering the quality, it is a remarkable change of visual
presentation in almost realistic time that leads to better
understanding of many spatial objects. Referring to the quantity,
it is the possibility of faster and cheaper production of a wide
range of various cartographic products. In manuals of
cartography various demands are stated that the cartographic
visualisation should meet.
4.1 Visualisation tools
While only a few years ago GIS-s used to have very modest
possibilities of cartographic visualisation, all higher quality
software for GIS enables today the production of maps. Thus,
along with other outputs from GIS, it is possible to produce a
series of modifications in the usual applications of topographic
and cartographic material for statistical needs, as for examples
for census and explorations, for thematic maps and graphic
simulations, etc.
Today, GIS supports more and more tools of graphic programs
and they have the tools for manipulating with objects, text,
retrieved objects, for special effects, export filters, etc. All
programs support also basic elements that are used for creating
a more complex drawing. These are the tools for drawing
rectangles (square being a special case), ellipses (circle being a
special case), general curves (straight line as a special case), for
creating bitmaps and writing texts. Special tools enable the
work in layers, creation of round edges of a rectangle, the
production of pie graphs, classifying and connecting, and
making single objects thicker or thinner, making them straight
92
or doubled, focusing, zooming, distance and angle measuring,
filtering for the purpose of improving image quality, masking,
shading, vectorization, rasterization, etc. (Lapaine and al.
2000).
Digital tools are being developed continuously, and hence, it is
expected that more convincing visualisation tools for the
presentation design will appear. So far, focusing has been
developed that is used for determining the contrast between
objects and environment, defining thereafter the limits of clear
distinctness. The accompanying effects are known as
disappearing, fogging, and similar. Furthermore, zooming has
been developed almost perfectly enabling the distinction
between graphic, contextual and intelligent zoom, and also the
work with the sections, windows, graphs and icons (Timpf and
Devogele, 1997). There are also animated figures, three-
dimensional representations, shading with various models of
illumination, e.g. flat shading, the method of intensity
interpolating (Gouraud shading), the method of interpolating
normal onto the surface (Phong shading), the method of ray-
tracing and the method of radiosity, blinking and glittering,
various filters, simultaneous representation of various
cartographic presentations, colour transformation and other
phenomena (Kraak and Ormeling, 2003).
The development of visualisation software requires, especially
for GIS and cartographic purposes, the research of real needs
and aim that users want to reach. Cartographers should take part
in scientific visualisation, as well as users and creators of tools,
leaning in it on scientific and professional cognition, but also on
individual skills. The tools of cartographic visualisation give
users the possibility to carry out extensive transformations and
changes of data presentation, e.g. different observation angle,
changing various conditions etc. enabling the comparison of
essential facts. It should not be exaggerated when using
visualisation tools. One should, namely, try to achieve visual
simplicity and, when it is not necessary, avoid any burdening of
a user.
4.2 Demands posed in GIS upon cartographic visualisation
Before the consideration and making of demands has
commenced, one should reflect upon our experience of a
cartographic presentation or upon what is necessary to
experience a cartographic presentation. This question touches
the essence of cartographic communication itself. According to
Ucar (1979), cartographic presentation is a visually very clear
and to a certain extent intuitive model of space. Cartographic
communication is graphical and visual communication.
It should be considered in this case that the sense of sight is
created on the basis of received impulses as completely psychic
event experienced individually. In order to have the sense of
sight become the experience of sight, some higher psychic
function should be involved as well, as for example memory,
abstraction and similar. Hence, it can be concluded that we
actually *watch" with brain (Knizhnikov, 1997).
In *classical" manuals of cartography, as for example are those
written by Peterca et al. (1974), Lovrié (1988), Robinson et al.
(1995) or Hake et al. (2002), various demands are stated that the
cartographic visualisation should meet. The following three
demands can be therefore demanded: legibility, plainness, and
accuracy. Apart from that, the cartographic visualisation should
meet also the demands that can be posed upon any graphic
presentation. The following is of the greatest importance for the
cartographic visualisation: clearness and aesthetics (Figure 3).
Each of 1
ingredier
more ade
has quite
the effic:
cartograp
of carrie
Franges €
made fo
plainness
of some «
The ord
importan
some are
successft
LE(
- minin
- graph
- difere
known
ACC
- positis
accurac
- accur:
Figure
Good car
defined s
and optin
users and
is especi:
according
the natur
should b
intensity
object, e
perfect, b
the map t
descriptic
Map sym
that the nr
