:al 
/e clearly and 
umpatibility with 
3 that can be per- 
Lnformation about 
Lon,climate,soils, 
, etc. of similar 
lcluding very im- 
data. 
selection:large 
Lief study and 
iispensable. 
;ion,supported by 
i highly speciali- 
:ion with field 
s study emphasis, 
correlation and 
perception le 
gation try to 
tendencies. 
tiled analysis; 
rocesses and 
;s. 
t with sup. percep 
;s and deviations. 
■1 variations 
elements. 
>roach and ten- 
allows identifi- 
and patterns,di- 
th reality, 
and its associa- 
iatial and morpho 
and constituent 
etails. 
spects that can 
images and its 
problem interpre 
be correlated 
ption level. 
ation scale 
ation priorities 
elements and or- 
ems and networks 
ropic processes 
y- 
eneous designa- 
d models. 
cartographic experiences, as a"'consequence obtained 
when small scale maps are carried out; it "is clearly 
perceived what can be seen-of-reality. 
Logically, in that perception level large geomorpho- 
logical units or relief forms assemblies and structu 
ral, lithological or bioclimatic important control 
effects can be perceived. 
By the way , according to the relation between the 
relief form size and its evolution time, paleomodels 
influence is far too strong particularly in the relief 
forms and the surface run-off networks. That is why, 
special care should be taken in the stablished co 
rrelations between the different geomorphic subsystem 
engaged, due to the fact that they represent different 
pasts. 
Care must be taken in small details observations or 
any kind of anomaly. What it is of interest.in this 
level is organization of models and nets as well as 
limits and/or transitions which the associated ele 
ments can indicate and not the isolated element it 
self . 
Consequently, we could say that what it is reflected 
in this level, whichever the considered aspect were, 
is the maximum degree of landscape space-time organi 
zation and so multi-interdisciplinary vision of imagery 
interpretation is required. 
At zonal level perception experience is not excesive 
ly far away from the everyday reality and it is near 
to one observed from an airplane by which interpreta 
tion is easier. Nevertheless as it was suggested in 
fig.2 reality perception reaches the maximum of 
complexity since, as it was already stated, the inter- 
venient factors influence the same or similar range 
of importance. 
Frequently, and as it was already seen, some element 
arrangements can be interpreted as provoqued by 
factors different from those which gave them origin. 
For example a clear depressions alignment which could 
be interpreted as of tectonic origin, may be of 
karstic, pseudo-karstic, eolic, etc. origin. 
For the same reason and in spite of that plain 
breaks of slope are so important, they are not always 
tectonic and when they are so, they can be displaced 
of their original position by means of erosion or 
paleoclimatic processes. 
Summing up we coul say that what it is reflected in 
this level is maximum correlation and the space-time 
interference between geomorphic and anthropic proce 
sses. From this point of view we could say that this 
perception level is the key for morphodynamic inter 
pretation an consequently for the system, natural ten 
dency and the anthropic influence. 
At local level perception is almost identical to 
the habitual one, and for the same reason the photo 
interpreter could get the ability to see "what he 
must see", that is to say, a great degree of special 
ization . 
This is the optimum level to recognize individual 
processes, microforms and smallest elements which 
integrate the landscape. 
Nevertheless it should be remarked that so as to 
finish this point, different perception levels are 
complementary, since at local level perception from 
organization space-time correlation and interference 
degree is minimum. 
Scale representation 
The last question formulated:Which scale is to be used 
in the presentation for work result? It leads us to 
one of the principal point of the paper. 
It can occur that interpretation were performed at 
one scale and mapping carried on in a similar one, or 
that a totally different scale were used for carto 
graphic representation. This makes us reiterate that 
the existence of an important analogy between imagery 
and.cartography. Both are realities -"representations" 
and then what, we have stated fbr different .-perception 
level imagery is .valid .for the cartography. 
That is to say, we cannot expect to obtain from the 
mapping elaboration process more than what reality 
can be reflected at that scale. This suggests the 
importance of the correct scale election and the pro 
blems than can be derived when image and map have not 
the same or similar scale. 
Another very important aspect of cartography is that 
it should represent by means of symbols or legends 
those géomorphologie basic aspects.: Morphometry, 
morphogenesis,morphocronology, morphotaxonomy and 
morphophysiology. In spite of that the taxonomic or 
perception leveldetermines the major and minor import 
ance of these aspects and the corresponding elements 
of each of them. It should be remembered that the pur 
pose of the study also plays its role. 
It is also necessary to remark, since it is not as 
much considered, the importance that correct and strict 
limit of géomorphologie elements represented, since 
correct model perception results from mentioned accura 
cy. All what was stated reaches more importance as far 
as work scale becomes greater. From that it can be 
deduced that detailed géomorphologie survey performed 
is important in every level, even when it implies the 
use of adequate symbology and appropriate generaliza 
tion at each of them. 
Taking in consideration that reality perception can 
be performed just as much as dimension scale, limits, 
forms and background and figure contrast are known. 
Then we can understand that when we speak about carto 
graphy, we want to point out that those aspects have 
to be correctly represented,so as not to risk the 
relations between models with non correct causes. 
Experience gathered from all performed plain works 
indicates how immensely important election is and/or 
géomorphologie symbology and legend preparation and 
more still when work is done of applied character. 
Difficult task constituted by thematic cartography 
causes numerous questions. The first of them is whe 
ther all those geomorphological aspects above mention 
ed will be represented by symbols, legends or both 
combined. 
The second is that the individual symbol or that 
associated in a model must in any way be related to 
habitual perception of geomorphological event or 
element to be represented. 
The third question stated is that the symbols or its 
association must reflect, immediately, the relative 
importance of what we want to represent. 
The fourth treates about linear elements must be 
represented with lineal symbols and in the same way 
the areolar ones. 
The fifth question is about legend which organiza 
tion must allow the comprehension of geomorphic pro 
cesses, dynamic and tendency thus pointing out domi 
nant process or agent, its temporality and the corres 
ponding form. 
Not intending to have an exhaustive enumeration, 
effective possibilities of printing elaborated carto 
graphy and the related problems, have to be considered. 
To that respect we lack possibilities for color print 
ing as well as the support of experienced cartographers 
for this task. 
About the cartographic elaboration, Verstappen points 
out: "The basic problem of the cartographic elaboration 
of geomorphological maps is the great variety in types 
of information that one could include. Restraint in 
this respect is an absolute necessity; otherwise the 
maps produce will be complex, costly in printing and 
difficult for the user to read. The limited range of 
cartographic means of expression restricts the tenden 
cies to undue perfectionism, although great care is 
always required to not overload the maps. Simplicity by 
emphasizing the most essential information and-genera 
lizing or omitting the less important should be the 
guiding priciple" Part of the information required may 
be included in the description of the geomorphological 
phenomena given in the legend and not in the map itself 
The above mentioned questions were gradually solved 
according to these large plains geomorphological cha 
racteristics which make the cartographic concept ela 
boration more difficult, particularly at semidetailed 
level (zonal level, the more complex). Due to its 
importance plains surface run-off system was studied