minmiMaiirfe
P. H. J. van den Boom - The railway and the map
In thispaper a review is given ofthefactors which have influenced
the course of railway lines and the pattern of rail networks. The
following categories offactors are distinguished: physicalfactors
like relief, natural barriers and soil conditions; social-economic
factors like concentrations of population, concentrations of
economic activity and the location ofcoal and iron ore mines; the
role of private interests and competition between private railway
companies; Strategie and military interests and the role of natural
boundaries.
Examples are given of all factors discerned, many ofthem
illustrated through a map. The examples come mostly from the
Netherlands but also other parts of the world are covered. The
purpose of the article is to give insight in the factors which
determine the patterns of traffic networks and to stimulate
cartographers and map users to look more behind these patterns.
L. A. Ankum, A. K. Bregt,J. Denneboom and Y. van Randen-
Gridded soil map of the Netherlands: gridding error.
The digital soil map of the Netherlands (scale 1 50,000) in
vectorform was gridded. For a valid use of the gridded soil map it
is important to know the size of the gridding error. This error
depends on the grid-cell size and the complexity ofthe map
pattern. For the grid-cellsizes 50 m x 50 m, 100 mx 100and200m
x 200 m the gridding error was estimated for 11 map sheets of
different complexityThis was done by the double-conversion
method and the Switzer method. The parameters ofboth Switzer
and Goodchild were used in the Switzer method.
The relation between map complexity, indicated by the boundary
index, and the gridding error for the three cell sizes (defined by
the double-conversion methodis presented as a regression
equation.
The double-conversion method provides a better estimation of
the gridding error than the Switzer method. The Switzer method
with the parameters of Goodchild gives a better estimation ofthe
gridding error than the Switzer method with the parameters of
Switzer.
R. O. Koop - Cartography on the microcomputer: Atlas
advanced mapping package
atlas amp is u Software package designed to produce
CHOROPLETH and DOTDENSITY maps on the IBM Personal
Computer (PC or A T) or on any compatible machine. The
Software is user friendly and offers many features which are
rarely found in PC graphics/mapping Software today.
atlas amp consists of three modules: atlas, the map design
and analysis System; mapedit, a module to create and modify
the boundary files andfinally dataedit, a special spreads-
heet program for entering and processing the (Statistical) data
to be mapped. The Software package Supports several plotters
and printers to generate hardcopy ofthe thematic maps
designed, with title, legend and additional text labels.
The cartographic perspective:
The Software and user manuals lack any kind of theoretical
cartographic basis to guide the novice mapmaker through the
relatively complex mazer ofthe theory of cartographic
communication as defined by Jacques Bertin. The inexperien-
ced mapmaker is thrown into thepool without any swimming
lessons. We feel that in the interest of the users of atlas amp
future releases must contain a chapter on this subject.
atlas amp is judged in general as easy to use and comfortable
to work with. Hopefully the package will evolve in the future
into a mapping package which supports more map types, like
bargraph and piechart cartograms. These cartograms will
allow mapping of absolute values, something absolutely
impossible with choropleths.
KT 1987. XIII.2
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