res u in es
w
Another method, which is called the 'smallest rectangle'-method
here, makes it possible to record with reasonable accuracy the
location of point-, area- or line-objects with only 1, 3 and 4
pairs of coordinates respectively. For the area- and point-objects
the smallest rectangles are defined in which those objects fit
precisely. With the coordinates of an arbitrary map extract as
input, the Computer is now able to select all objects (partly or
completelywithin that map extract. Some inaccuracy is
inevitable, as rectangles are usually larger than the objects
themselves. On the other hand, this method will save a lot of
storage space.
L.H. van Opstal - Developments in the automation at the
Hydrographie Office
Automation at the Hydrographie Office started in 1970 with in
particular depth sounding at sea. The processing and quality
control takes place on board ship with the Hydraut-11 System. In
1984 a Start was made to set up a qualified database for
Position and other mapping data of buoys, lights, shipwrecks,
etc. To obtain experience for further decision making a small
series of charts was digitised by raster scanning by a private
firm. In 1986 the very advanced interactive charting System
CAR1S was introduced.
In 1987 under governmental pressure of manpower reduetion a
Start was made to speed up the automated produetion of charts
for coastal waters and inland waterways. As the raster-vector
conversion is still unsatisfactory the charts are manually
digitised.
In the near juture classical navigation will be replaced by
interactive digital navigation Systems. The electronic chart will
then be integrated with positioning, log, compass and possibly
radar. Intemationally specifications are being set up to replace
the paper chart by the electronic chart. The Hydrographie
Office has the intention together with others to publish a digital
nautical Information System for the North Sea.
The future will be digital. A regional or possibly a world data
base for an electronic chart (ECDB), continuously revised, will
be transmitted by satellites.
Next year a project group from the 8 hydographic ojfices around
the North Sea will Start the design of such an ECDB for the
North Sea, including distribution and revision.
On the national level the Jurther development of GIS will lead
to a closer Integration of land and sea information.
W Tirion - Uranography; the cartography of the heavens
The oldest star maps show us in the first place the artistic
representation of the old traditional and mythological
constellation figures. Our oldest constellations originale from
Mesopotamia and Greece. Between 1600 and 1800 many more
were invented and added to the traditional ones. After the
invention of the telescope the need for more accurate maps grew
and the constellation figures slowly disappeared. A modern sky
atlas shows dots and symbols, representing stars and objects.
In the 20th Century many Photographie star atlases have been
made, some very expensive, others within the reach of most
amateur astronomers. But a demand for hand-drawn atlases
remained. Another way to produce a star atlas is by using
Computer techniques. But even then a skilled uranographer is
needed to give the charts an attractive and readable
appearance.
Wil Tirion is author of, inter alia, Sky Atlas 2000.0 and
Uranometria 2000.0.
P.C.J. van der Krogt - The GO-H training programme in map
and atlas curatorship
Maps and topographical atlases demand a special kind of
curatorship. In co-operation with associations of curators of
map and topographical/historical collections, the GO-Institute
for part-time professional education in library and information
sciences in Den Haag started a special course in map and atlas
curatorship in 1987. In the article, the curriculum of this course
is described in detail.
M I. Kraak - Le Systeme cartographique 'expert': un bref
apergu
Un des resultats de l'application de l'ordinateur en cartographie
est l'aumentation considerable nombre des cartes produites. A
premiere vue, les cartographes considerent ce phenomene
comme une evolution positive. Toutefois, en ce qui conceme la
qualite de ces produits, il y a des reserves faire, non pas tel-
lement en raison des difficultes techniques, mais du fait que les
'nouveaux' cartographes - les utilisateurs - ne disposent pas
toujours de la formation cartographique requise.
Le Systeme dit 'expert' pourrait apporter une Solution ce Pro
bleme car il ojfre la possibilite en tant que partie integrante par
example d'un Systeme d'information geographique, l'utilisateur
non-cartographe d'illustrer son rapport par des cartes de qualite
acceptable.
L'article analyse une serie de notions telles que Tintelligence
artificielle, les connaissances, la strueture et les caracteristiques
des systemes 'expert' et leur application dans le secteur de la
cartographie. Un exemple pratique illustre, enfin, l'analyse: la
revision d'une carte marine l'aide d'un Systeme 'expert'.
R. van der Schans - Depuis la carte mentale la base de
donnees
Inspire par l'ouvrage de Lockard Design Drawing, l'auteur trace
le cadre historique du developpement des systemes d'information
geographique. II y a quelques annees, l'avantage essendel de
l'automation de la cartographie semble avoir ete l'allegement
des travaux manuels fastidieux. Aujourd'hui, toutes les donnees
digitalisees peuvent etre udlisees dans un veritable Systeme
d'information, introduisant une plus grande flexibilite dans le
dessin et l'analyse cartographiques.
Cependant, l'utilisateur du Systeme fait partie d'un Processus de
communicadon, en faisant appel une base de donnees geogra-
phiques. La carte mentale, le resultat de ces donnees une fois
enregistrees, reste gravee dans son cerveau. Nonobstant donc
l'insertion d'une technologie fort complexe entre la collecdon,
manipulation et la representation des donnees, les 'vieilles'
theories de la communicadon cartographique restent toujours
valables, aujourd'hui.
KT 1988.XIV.4
67
