geomorphologist is not tempted to pretend greater chronological accuracy than
really exists, as may be the case when chronology is linked to colour. Morpho-
metric data are largely discarded by pecsi.
In Belgium (p. macar, 1961) morphometric information is the hard core of the
maps and slope steepness classes are indicated by coloured area Symbols. One
may with justification say that too much emphasis is thus laid on an aspect that
certainly is not the essence of geomorphology. As a consequence insufficient means
of cartographic expression are left for genetical, chronological etc. data. One
should, however, not forget that slope classes are absent on most other geo-
morphological maps. A transparent overlay with slope classes is often promised
to overcome this drawback. It is, however, seldom made and if so, is awkward
to handle.
It should be mentioned that in this country maarleveld is producing a geo-
morphological map at the scale of 1 50,000, for which a special key was devised.
c. The ITC System of geomorphological survey
When at the ITC geomorphological maps were made from many different parts
of the world, it became clear to the author that none of the existing legends was
fully satisfactory in the sense of being universally applicable because the geo
morphologist was forced in a too rigid harness. A method thus gradually developed
in which some ideas of existing legends were incorporated but that soon became
a true mapping System with distinct characteristics and embracing a variety of
map types.
Desiderata for the System were the following:
1. It should be applicable in the most diversified types of terrain and thus instead
of giving an exhaustive list of Symbols, etc., the system should be flexible and
several decisions should be left to the discretion of the author of the map.
Otherwise it might easily occur that the most suitable symbols, colours etc.,
cannot be applied because they have been reserved for phenomena that do not
occur at all in the area.
2. The maps produced should be as simple as possible so as to avoid in many
countries practically unsurmountable cartographical problems and high cost
of printing.
3. The system should be applicable for mapping on all scales. Evidently the
Contents of the maps changes with scale. On small-scale maps symbols for
small-sized features automatically have to be omitted or to be replaced by
group symbols etc. At the same time the accent will come to rest on major
landform units and morphostructures.
4. 'Standard' geomorphological maps should be complemented by special pur-
pose, applied maps, simultaneously produced. Applied maps have been devised
specifically for conservation and for hydrological purposes.
5. It was thought advisable to bridge the gap between analytical geomorphological
mapping and the well-known landsystem survey. Therefore the coloured area
symbols were reserved not for lithology, chronology or the like, but for major
genetic landform units, since these tend to coincide with landsystems or units.
88
Introduction to the ITC System of geomorphological survey
K.N.A.G. Geografisch Tijdschrift IV (1970) Nr. 1
