You are using an outdated browser that does not fully support the intranda viewer.
As a result, some pages may not be displayed correctly.

We recommend you use one of the following browsers:

Full text

Remote sensing for resources development and environmental management
Damen, M. C. J.

Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
Use of remote sensing for regional mapping of soil organisation data
Application in Brittany (France) and French Guiana
Centre Scientifique IBM France, Paris
Société Européenne de Propulsion, Paris, France
ABSTRACT: Two analysis showing the coincidence between soils organisation data and remotely sensed images are
presented, the hrst one in Brittany and the second one in french Guiana.
RESUME: Deux analyses montrant la coïncidence entre des données d'organisation des sols et des images de télédétection
sont présentées, la première en Bretagne et la seconde en Guyane française. ^
The aim of this study, which started in 1983, is to fmd and then
use the information related to local soils organisation data
obtained from remotely sensed images, to extend the local
knowledge and mapping of soils, at a regional scale.
This long term research is being carried out; the first results
are presented.
1.1. Situation of the study and general methodology
The presented work concerns a 32 ha. area in central Brittany
(France). Its morphology is made of a plateau, a northern
slope and a downstream flat level. It is constituted by a
Gedinnian and inf. Siegennian anticlinal of schists and
quartzites, and covered with heath and fernery.
This work w r as made in two parts
1.1.1. A ground reference constitution
1. Concerning the superficial formations organisation
This organisation is modelised threw:
Ground observations of 165 profiles and 9 trenches. The
different organisations volumes are described, the limits
between the volumes are geometrically drawn, allowing an
analysis of their relations.
Microscopical and chemical analysis have load us to precise
the characterizations, and to determine some processes of
différenciation and their chronology.
The limits between the different organisations volumes have
been spatially followed by numerous observations.
2. Concerning the distribution of vegetation:
A map of the spatial repartition of the main vegetal unities
has been performed, through the interpretation of an aerial
infra-red photography, and through ponctuai observations
inside the homogeneous regions and on their limits. Each limit
of this map has been analysed from the point of it significance
depending on vegetal competition, human impact, or relation
with the superficial formations.
1.1.2. Image study
The infra-red photography was obtained during an aerial mis
sion required to be at the scale of 1/20 000. This photography
was digitised by a microdensitometer, in two different images,
in such a way that a pixel represents a square at the soil surface
of 50x50 cm for the first image, and of 90x90 cm for the second
one; each was digitised in three channels, red, green, blue for the
reflectances in infra-red, red, and green respectively. These
images were prepared by contrast enhancement treatments. The
cadastre, the map obtained by the study of superficial for
mations and the vegetation map were registered on both ima
ges. The treatments tested with the aim of expressing the
information related to the ground reference were of two kinds:
1. Statistical treatments on the reflectances.
2. Textural treatments.
1.2. The ground reference .
The ground reference study led us to propose three main results.
1. The first one concerns the organisation of the alteritic for
mations in three domains. The limit between the first two,
developped on the plateau and the slope, is of geological sort,
it shares a domain with weak weathering on hard grey schists,
and a domain with a very developped and deep weathering, on
more alterable schists alternating with quartzite. The limit
between these two domains and the third one, lying
downstream, is the one of an hydromorphic transformation,
which affects the two previous domains by a mobilisation and
a concentration of iron and clays. A localised zone on the pla
teau is equally affected by this transformation, which results
from the beating of the permanent water sheet.
2. The second one concerns the relations between the surface
différenciations and the structure of the alteritic formations
described above. In facts, the pedological limits reflect this
profond structure. Some limits are purely superficial
différenciation ones, but by the study of the alteritic structure,
we are allowed to define, among these superficial limits, which
one are revealing the internal structure of the whole volume of
the superficial formations. On the map presented below, we
have overmarked these structural limits.
Figure 1 : Map showing the structural limits of superficial for