resumes
67
H.J.G.L. Aalders - Overview and applications of optical
storage techniques
The application of optical storage techniques enables the
massive storage of data in digital cartography. This article
reviews optical storage techniques and their possibilities refer-
ring to CD-ROM, CD-I, videodisc and the Digital Optical
Record (DOR). A typical System configuration is described as
well as an appliction in ofßce automation. Finally, the actual
Standards for optical storage Systems are discussed.
Old and obsolete maps; map curatorship and archives
M.A. Bakker - The Law of Records, inspection and destruc-
tion of maps and drawings
to keeping archives are treated, as well as the municipal regula-
tions concerning the management of archives. In the second
part of his article he deals with the types of maps and drawings
which are found in the institutions' archives and the respective
methods of conservation. Finally, the problems of selection for
destruction and Photographie Substitutes of the various map
types are described.
In the Rotterdam Public Ofßce maps and drawings are stored
with the collection of pictures of the city: the Topographical-
Historical Atlas.
Ratsma first explains the difference between map records and
collected maps. He outlines the ways by which the Attas was
gradually built up and gives examples of its pertinence for
historical research. Finally, he deals with the management of
these maps, distinguishing acquisition (of complete archives),
accessibility (of files and documents) and conservation.
P. Ratsma - Management of map records in the Municipal
Records Office of Rotterdam in particular
Maps and drawings made, or used, by government institutions
are kept in the archives of those institutions for longer or
shorter periods. These maps and drawings are bearers of infor-
mation and represent an investment of labour, time and capital.
After some time they are no longer topical and may, perhaps,
only retain an historical importance. In such cases, after selec
tion and destruction, the archives are removed to a public
records office.
Bakker's article deals with the care of maps and drawings while
they remain deposited in the archives of the institutions;
Ratsma 's paper treats their management in a public records
ofßce.
Bakker, Inspector of Archives at the city of Rotterdam, begins
with an explanation of the general and legal reasons for this in-
volvement with maps. Afterwards, some technical terms related
J.A.M. Schepers and A.A. de Veer - Cartographic integration
of morphometry and degree of openness in the landscape
map
Morphometry and degree of openness are two major aspects of
the visible landscape. The article describes a method to in
tegrale both aspects taken from separate, existing maps into one
new landscape map. An example of such an integrated map is
enclosed in this issue of the Kartografisch Tijdschrift (part of
southern Limburg at scale 1:50,000).
Morphometric units, derived from a geomorphological map, are
displayed in colour and with letter codes. Degree of openness,
derived from a topographical map with fieldcheck, is given in
the form of a cross-hatching and with numbers. Integrated maps
can be used for suitability and evaluation studies. It is also
possible to study the (causal) relationship between geomor-
phology and openness of the landscape.
J.H. Geels - Un modele pour selectionner les symboles de
surface
C'est la seconde partie de l'article traitant de la methode de
selection des symboles de surface adhesifs. La premiere partie a
ete consacree la terminologie tandis que le lecteur trouvera,
ci-dessus, quelques exemples et regles. Pour d'autres details:
cfr. le resume de la premiere partie (Kartografisch Tijdschrift
1987. XIII. 4).
L'auteur est la disposition des lecteurs pour plus amples infor-
mations (en anglais).
Le modele est visualise dans le diagramme, joint au resume
anglais (p. 66).
Niveau de mensuration
Definitions:
Echelle nominale: un ensemble d'objets identifiables sans in-
dication de leur interrelations. Operation typique: equivalence.
Exemple: religion.
Echelle ordinale: une echelle nominale dans un ordre indique.
Operations typiques: superieur, inferieur. Exemple: niveau
socio-economique.
Echelle d'intervalle: une echelle ordinale avec graduation.
Operations typiques: addition, soustraction. Exemple:
temperature.
Echelle de 'ratio' (proportionnelle): une echelle d'intervalle avec
indication de la proportionnalite. Operations typiques:
multiplier, diviser. Exemple: temps (heure).
Regles:
Utiliser une variable visuelle 'pure' dont le niveau de mensura
tion correspond celui des donnees statistiques. Si Ton choisit
une variable visuelle avec un niveau inferieur de mensuration, il
y aura pertes d'information. Dans le cas contraire, en choisis-
sant une variable visuelle avec un niveau superieur de mensura
tion, il faudrait creer de nouvelles informations (donnees).
Commentaires:
Les niveaux de mensuration forment une hierarchie, d'oü la
possibilite d'eliminer un ou plusieurs niveaux, ce qui conduira
de pertes d'information, notamment de Celles correspondant
I'Operation typique du niveau abandonne. II est donc recom-
mande d'utiliser le niveau de mensuration le plus haut possible.
La creation d'une image suppose Tutilisation des 'tailles' ou
valeurs, celle-ci etant toutefois limitee au niveau superieur de
mensuration (echelle d'intervalle et de 'ratio').
Comment parachever la creation d'une image aux niveaux in-
ferieurs echelle nominales et ordinales)? Vous pourriez vous-
meme 'gonfler' le niveau de mensuration! Echelle nominale de-
viendra ordinale si vous adoptez d'organiser vos donnees Selon
un certain ordre.
