Programme System is a set of drawing programmes already in use within Rijkswater-
staat for a number of years. Various other governmental organizations and institutes
participated in the development of the Programme System, in order to make it suitable
for applications in various disciplines.2 The programme System is called AUDIMAP,
and derives its name from awtomatic digital mapping.
The System consists of a number of programme modules, which perform the various
basic tasks in digital mapping.
THE BASIC UNITS OF THE PROGRAMME SYSTEM
The programme modules perform the following tasks (see fig. 1):
- The drawing of the title, margin and grid lines on the map sheet.
- The transformation of the co-ordinates of the data points into the System of the
map, and into the System of the plotter.
- The drawing of lines, texts and Symbols. There is an Option to draw straight line
sections between the given data points, or to interpolate smooth lines. The method
of smooth line interpolation is based on piecewise polynomial functions and is
described by Ahlberg et al. 1967. The user can specify any type of line symbol he
requires to be drawn. The texts and map Symbols can be drawn in various sizes and
orientations.
- The Omission of information outside the margin of the map (scissoring).
- The representation of thematic information.
- The interpolation of contour lines from a set of given data points. The drawing of
the contour lines is always preceded by the computation of an analytical
expression of the surface to be contoured, cf. Kubik 1971 and Bosman et al. 1971.
All these programme modules have been programmed within Rijkswaterstaat
according to the specifications of the users, since it was found that the commercially
available modules did not satisfy their high requirements.
THE DATA SETS AND THE DATA MANAGEMENT PROGRAMME
The data supplied as input to the programme System are collected in data sets. We
distinguish various data sets:
One data set contains the legend of the map; it is a list of all map Symbols along
with a code number for each symbol. New map Symbols may be added to the list by
the user according to his needs.
Another data set, which is compiled by the user, contains the geographical names in
the project area, which have to be written on the map sheets. Each expression is
accompanied by a code number.
Finally there is the large data set containing the metric geographical information.
Because this data set is very large indeed, it is usually subdivided into smaller subsets,
which then refer to a local part of the area only. The information in these subsets is
stored in three columns, containing the code numbers,X-co-ordinatesand Y-co-ordi-
nates of the registrated points.
The code number specifies, whether we have to deal with a point of a line, symbol
or text. The code number may refer to the legend of the map. If such a code number
occurs, then the map symbol stored in the legend under this particular code will be
placed at the recorded point. Alternatively, the code number may refer to the data set
K.N.A.G. Geografisch Tijdschrift VI (1972) Nr. 3 299
