J. J. C. Piket - CARTOGRAPHIC GENERALISATION AND
CONSEQUENCES FOR MAP CONTENTS
Thls paper has been presented in Exloo at the 1985 Study Days
organised by the Dutch Cartographic Society (NVK)It deals
with the hlstorical development and actual methods of genera-
lisation. It is demonstrated that the distinction between pic-
torial Symbols ('signatures') and abstract Symbols is a sig-
nificant one in generalisation.
The comparison of topographic map extracts on sequential
scales from 1 5,000 to 1 15 million leads to the formulation
of four main rules of generalisation:
- Asynchrony. On topographic maps the change from graphic
to conceptual generalisation has an asynchronous character
relative to topographic features. The sequence of change
appears to be as followsroads first, secondly Settlements
and thirdly land characteristics.
- Quantification of map contents. On the map, continuing con
ceptual generalisation leads to conversion of qualitative data
into quantitative data.
- The more conceptual generalisation continues, the more the
older topographic phenomena displace younger ones. E.g.
location and toponyms of a settlement, being aspects of its
origin, progressively replace the representation of its actual
structure.
- Continuing generalisation goes with the replacement of point
and line Symbols by areal Symbols.
M. J. Kraak - COMPUTER-ASSISTED CARTOGRAPHY AND
GENERALISATION
This paper has been presented in Exloo at the 1985 Study Days
organised by the Dutch Cartographic Sociely (NVK)It deals
with the possible role of the Computer in solving problems of
map generalisation. The author first of all tries to give an
answer to the question: 'What is generalisation?'. Then he
mentions some examples of existing computer-algorithms
which deal with some aspects of generalisation: the simplifi-
cation of lines (vectorbased algorithms) and the simplification
of areas (raster-based)
At the moment all problems of map generalisation cannot be
solved with the help of a Computer, but in various ways Com
puters are and will be of great use.
F. Depuydt and M. Paulissen - GENERALISATION OF ORO-
HYDROGRAPHY
One aspect of the comparability of topographic maps at scales
1 100, 000 - 1 250, 000 is the way of generalisation. This
paper may be considered as the report of an investigation of
the methods for the generalisation of the river network and
contour line pattern, as applied in 9 different countries.
Emphasis is laid upon the most important aspect of the gene
ralisation of the river network: selection. A major conclusion
which emerged was that in the topographic maps analysed no
systematic (quantitative) and uniform selection of the river
network could be discovered. Important differences do not only
exist between the selection procedures applied in various coun
tries, but also within the topographic map series of countries
themselves.
Heterogenious generalisation may be explained by the lack of
(the application of) Standard procedures. The very use of con-
crete selection formulae could already lead to more uniform
generalisations. Another conclusion was that the generalisation
of the contour line pattern in relation to the generalisation of
the river network was not satisfactory in all maps analysed.
R.T.-de Wijs - CARTOGRAPHY AT HTS UTRECHT
In 1984 a first group of students successfully completed a new
study Programme in cartography of 4 years duration at the
'Hogere Technische School' (HTS, comparable of Polytechnic)
in Utrecht.
Previously, in The Netherlands no cartographic training or
education existed at this level. Next to a discussion of the em-
ployment of graduates and the general level of education, this
article briefly describes the elements of the study Programme.
The first year's Programme is common to that of surveying.
After the first year students specialize in cartographyPrac-
tical periods of 200 working days in total form a major part of
the Programme. By means of final projects it is possible to
assess whether the objectives of the study Programme are
reached. An example of such a final project 'Häven van Rot
terdam') is enclosed and separately described in this issue of
the 'Kartografisch Tijdschrift'.
KT 1986. XII. 1
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