1. Morphographical information:
The forms should be identified from a geomorphological point of view, for in-
stance: river terrace, erosion surface, etc., which is not the case on a topographical
map. Since the identification of forms is often based on their mode of formation,
the morphographical aspect is closely related to the morphogenesis mentioned
under heading 2.
2. Morphogenetical information:
The forms should be represented in such a way that their origin and development
is immediately clear. In the legend accompanying the map descriptive indications
like 'sandy piain' should be avoided and genetical descriptions ('sandy alluvial
piain; sandy pro-glacial piain') should be used instead. Since forms are the out-
come of the effect of geomorphological processes, these should also be mapped.
Lithology and geological structure also merit füll attention, because of their
often profound effect on forms and processes.
3Morphometrical information:
Topographical (contour) maps give much essential information in this respect and
thus the geomorphological map can best be printed on an orohydrographical base,
but certain geomorphologically important data, such as height of trough Shoulders
or river terraces have, however, to be added. Slope steepness is another important
element that will be dealt with in paragraph b.
4. Morphochronological information:
Since every form is characterized by the period of its formation and further
development, it is essential to make a distinction between forms of different ages,
in particular between recent forms and those forms inherited from earlier periods
when different climatic conditions prevailed. It is essential to keep the indications
for age flexible since it is the part of the map that is most apt to need revision with
the advance of geomorphological knowledge.
It should be stressed here that with a few exceptions (e.g. USSR) the attention in
the beginning was devoted almost completely to large Scale mapping in scales
ranging from 1 10,000-1 100,000. Considerable (though not completely success-
ful) efforts were given to unify the legends used in various countries or at least to
make them more comparable. Particularly the Sub-Commission on Geomorpho
logical Mapping of the IGU Commission on Applied Geomorphology was active
in this field, and ultimately a Special Committee of this Sub-Commission made an
attempt to arrive at an unified key to the detailed geomorphological map of the
world (1968). One may question whether any key, elaborated into the smallest
detail, can really be applied all over the world but the attempt in itself is already
valuable. Of particular importance is the fact that coloured area symbols are used
for the large morphogenetic groups of landforms. Various hues of these colours
are then used to indicate classes of slope steepness. Lithology and structure are
mapped, but receive less emphasis. The newly (Delhi, 1968) established IGU-
Commission on Geomorphological Survey and Mapping has selected the com-
pilation of a small-scale 1 2,500,000 geomorphological map of Europe as one
of its principal aims.
86
Introduction to the ITC system of geomorphological survey
K.N.A.G. Geografisch Tijdschrift IV (1970) Nr. 1