North Sea flood control, water conservation and build
ing, maintenance and management of waterways,
roads, harbours, dikes, tunnels, bridges etc. As far as
construction works are concerned, the Rijkswaterstaat
acts as designer and supervisor. The actual work is car
ried out by contractors.
The responsibilities of the MD are:
the production of maps serving as a basis for the
design and maintenance of roads, canals, rivers,
dikes and dunes;
the maintenance of the network of NAP benchmarks
(NAP stands for Amsterdam Ordnance Datum);
- providing geodetic assistance to the Rijkswaterstaat
by carrying out measurements and computations for
purposes other than mapping, like construction
works on land, sea and rivers, which includes marine
geodesy;
- managing and maintaining radio location systems;
the central management of surveying instruments
used by the Rijkswaterstaat;
- research, advising and supplying information regard
ing modern observation techniques (e.g. remote
sensing).
Most activities of the MD are within the scope of the
Rijkswaterstaat, only a few activities reach beyond that
scope. The production of the river map and the main
tenance of the NAP network for instance have a general
purpose. Other maps like aeronautical maps are pro
duced for other governmental agencies.
After this general outline I will specify some of the
activities of the MD.
Map production
The data needed for map compilation are (sometimes in
combination) obtained:
- in a terrestrial way by measurements in the field;
in a photogrammetric way by measurements in aerial
photographs.
With the above mentioned data the cartographer drafts
or completes the maps (graphic mapping). Part of the
mapping production is carried out by recording the
results of photogrammetric and field measurements in
a digital file, whereupon the map is produced semi-
automatically (digital mapping).
In order to be able to provide up-to-date maps, revision
measurements are carried out periodically. The maps
are revised in accordance with the results of these
measurements. If the modifications are far-reaching a
completely new map is issued.
Base map
These maps give a description of areas to be used for the
designing of new works, such as roads or canals. The
mapped area is restricted to the terrain needed for
construction purposes. The maps give many details,
including heightdata. These data are often given sepa
rately by means of cross- and longitudinal profiles.
Management maps
These maps describe objects for management purposes.
The scope of these maps is restricted to the area
concerned, with a small bordering zone. Examples are:
Road maps
The Rijkswaterstaat is in charge of the management for
about 4500 km of highways and other mainroads. Each
map covers 1 km (scale 1 1000).
River maps
The history of this map goes back to 1829. In this year it
was decided to compile a map in the scale 1 10000 of
the waterbed (including the maindikes) of the principal
rivers. Nowadays river maps are made on scale 1 2000
or 1 5000. The river map exists of 358 sheets.
Coastal maps
The map (scale 1 2000 or 1 5000) includes the water-
line at high tide, all construction works for the defence of
the coast line and a small adjoining zone. The coastal
mapping covers the Dutch sea coast and consists of
about 80 sheets.
Vegetation maps
In order to make an inventory of the environmental and
ecological impacts of civil-engineering projects geo-
morphological and vegetation maps are produced. The
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