development a beginning was made with the systematic inventory of the North Sea
floor.
DEMAND FOR NEW CHART AND MAP MATERIAL
With the initiation of these and other activities concerning the State water
management aspects of the North Sea, a great lack in available chart and map materials
was evident. In fact, only the Charts at various scales published by the 'Hydrografische
Dienst van de Koninklijke Marine' (Hydrographie Service of the Royal Navy) were
available. Chart scales and chart projections as well as the inavailability of film
transparencies were a handicap for the execution of the management task. This task
consisted, among other things, of gathering all kinds of data dealing with the Dutch
part of the Continental shelf of the North Sea and the plotting of drilling sites, pipe-
lines, telephone cable right-of-ways, designated specific areas for shipping routes, sal-
vage ammunition dumping and anchorage areas. To do this plotting, film transparancies
on stable material and at uniform scales and projections covering the entire area were
minimally rquired
In co-operation with the Hydrographie Service of the Royal Navy and the
'Meetkundige Dienst' (Surveying Department) of the State Waterboard an entirely new
series of so called 'Documentation Sheets of the Continental Shelf was designed and
developed to fill these requirements. These Documentation Sheets appear at a scale of
1 50 000 on the U.T.M. (Universal Transverse Mercator) projection and with a fixed
sheet coverage of twenty minutes longitude by ten minutes latitude (see fig. 1).
DESIGN AND REPRODUCTION OF THE DOCUMENTATION SHEETS
The produetion of Documentation Sheets started with the automatic plotting of
the geographical grid and Decca pattern at the Surveying Department of the State
Waterboard. From the translucent Computer drawing three direct contact diapositives
(tracings) were produced by diazo printing on which various kinds of information
could be plotted: one tracing for the coastline, beacons and telephone cables, another
for geological information and the third for boundaries of mining areas.
This method was not quite satisfactory because these kinds of tracings have only poor
dimensional stability. In addition, they could only be copied separately by diazo prin
ting. Because of these disadvantages it became desirable to look for a better
method of reproduetion. Moreover several other offices, agencies and oil companies
showed growing interest for this kind of information on the condition that it could be
obtained on stable film copies.
After an inquiry by the Surveying Department a useful reproduetion System was
found at AGFA Gevaert Ltd. at Antwerp. In this process (the so called wash-off proce-
dure) two and more drawings on stable material can be combined simultaneously and
individually to make one negative. From this negative a positive can again be made. In
addition, one positive can be made directly from various negatives. The application of
this new reproduetion System was accompanied by a completely new design for the
Documentation Sheets.
This technique opened up the possibility to bring together specific subjects on one
drawing and to use another film sheet for other subjects (see table A). These divisional-
sheets can be combined with the new technique to one map. When one subject changes
only the sheet with the particular subject on it has to be corrected to make a complete
K.N.A.G. Geografisch Tijdschrifl VI (1972) Nr. 3 277
