Survey Department of the Ministry of Public Works,
Provincial Public Works and Netherlands Railways.
With the laying of the main system of natural gas pipes
private survey bureaus were involved.
I estimate, that in this period of 12 years an amount of
about D. fl. 50 million was put out to contract for the
execution of surveying and mapping activities, by the
Netherlands Gas Union.
Water management
For the sake of the water management a lot of levelling
takes place. With re-allocation and land reconstruction
the water management often must be adapted.
Instructed by the Land Reconstruction Authority of the
Ministry of Agriculture and Fisheries detailed contour
survey maps are made of these adaptations and site
inventories are carried out with regard to the recon
struction of new country roads and watercourses.
These works are generally supplied by the bureaus that
are concerned with design of the plans. Incidentally,
such activities are also being assigned by Polder Boards
and Drainage districts, in case that only the water con
trol needs to be improved.
Mapping and levelling of extension and reconstruction
of towns and villages
For reconstruction, and making extensions of roads in
towns and villages suitable for building as well as for
urban renewal, an inventory of above-and underground
inmovables is required.
The municipality concerned will carry this out itself, or
use private bureaus if their own capacity is insufficient.
A considerable increase of survey activities and activi
ties concerned with town planning resulted from the Act
on Physical Planning of 1965, that obliged municipali
ties to draft designation plans.
Since in many cases the cadastral mapping material
turned out to be of insufficient quality to give a good
technical execution to the plans, gradually the thought
grew with the technical departments of municipalities
that a precise situation and contour map at a sufficient
scale was badly needed. For these activities private
firms were employed as well. Firms that rendered var
ious services to municipalities were often favourite for
the execution of these surveying activities.
Large scale basic map of the Netherlands
The macro-infrastructure with regard to our system of
main roads, canals, railways, natural gas and high ten
sion cables is practically complete. An efficient manage
ment of these important veins of our economy however
requires a registration system that will be more and
more accessible and preferably uniform. This holds for
the above and underground regional cable and pipe-
systems in our country as well. The importance of uni
formity of the registration of immovables is realized
more and more and will lead to management maps and
records.
A powerful impulse to this so much desired uniformity
was given in 1975 by the Minister of Housing and Phys
ical Planning, who assigned to the Cadastre, the making,
issuing and updating of the large scale basic map of the
Netherlands (Grootschalige Basiskaart van Nederland,
GBKN).
The Cadastre is aided in this task by a central surveying
council and 11 provincial surveying committees. In this
advisory body the principal persons concerned are re
presented. The map is a large scale map, based on the
national system of co-ordinates, with such a topo-
NGT GEODESIA 82
graphical content, that it may be the basis of informa
tion, storage and processing for many authorities, in
stitutions and companies.
Finally a linear map in the size 50 x 100 cm was chosen,
with a limited content: road bordering, pavement, water
courses, buildings, bridges, property bounderies,
groups of trees, as well as semantic information as
streetnames, numbers on houses and closed and open
road pavements.
So far, the making of the maps takes place by way of
project; a condition is namely, that the maps have to be
paid for completely by the users (among which the Ca
dastre itself). The purchasers will have to reach an
agreement in advance about the cost distribution.
In practice mostly a photogrammetric way of establish
ment is applied. Despite the strict financial conditions
stated, a satisfactory production has been achieved
within a limited number of years.
At the moment over 10% of the surface of our country
has been mapped. The maps established up to now, are
mostly in the scale 1 1000; in rural areas, however, the
map often resulted from enlargement from mapping in
the scale 1 2000.
In built-up areas the maps are made in the scale 1 500.
Up to now, the maps are supplied in an analogous form.
So far, the updating of the maps has been arranged
separately per project.
On the part of users, who are working regionally or
throughout the country, objections have been made
against the project approach. In connection with their
own activities these buyers are interested in a more
systematic approach of making and updating the large
scale basic map of the Netherlands.
Within the central mapping council it was endeavoured
to formulate the conditions for a systematic approach of
the large scale basic map. This did not workout, since in
actual practice there turned out to be some bottlenecks.
It was decided to investigate these bottlenecks further in
the period of 1979 up to and including 1981, in about 20
pilot projects.
One of the most important bottlenecks is: how should
the map be defined? Purchasers could up to now only
choose between a completely field checked or a non
field-checked map, the purely photogrammetric result.
Field checking refers to the completion and correction of
the photogrammetric map. The purely photogramme
tric map forms a less suitable basis for the exchange of
information. The completely field checked map is at
least twice as expensive as the purely photogrammetric
map.
A compromise may be found by means of recording the
so-called „hard topography" (buildings and structures)
with geometrical precision. Besides, aspects like preci
sion, reliability, completeness and content will get
ample attention in the investigation.
The actuality of the map has also been further scrutiniz
ed for the sake of the programme of updating.
The final bottleneck I will mention is the conversion
problem of the cadastral map. Up to now the Cadastre
charged private bureaus with surveying and mapping of
this large scale basic map.
Involvement of these companies results from the past,
when the making of large scale maps in our country was
practically exclusively carried out by these bureaus.
By July 1st 1981 over 4000 maps were completed and
over 5000 maps were being produced. Put together, this
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