Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 4 Renewable resources in rural areas: Vegetation, forestry, agriculture, soil survey, land and water use. Chairman: J. Besenicar, Liaisons: M. Molenaar, Th. A. de Boer

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Use of remote sensing for regional mapping of soil organisation data Application in Brittany (France) and French Guiana. M. Dosso, F. Seyler

Document type:: Multivolume work

Structure type:: Chapter

422 3. The third one concerns the repartition of the vegetation. Studying the significance of the limits, we were led to distinguish the limits which are related to the superficial for mations, among the others limits which reflect the vegetal competition between species, or the way the ground has been used by man. The two figures below show the vegetal limits related to structural limit of superficial formations (overmarked figure 2) and the spatial coincidence between these limits (overmarked figure 3), and the structural limits (figure 1). .1 ___ s Figure 2 : Soil and vegetation sequences Therefore it seems possible to express in the aerial photography, the proper information on the structure of the whole volume of superficial formations, by the intermediary of the surface différenciation and the vegetal cover repartition. 1.3. The methodology defined for image processing The first group of treatments applied to the images, were seg mentation on the plane of the reflectances, by establishing different classes of vegetation, in one dimension (primary channels, channels combined by vegetation index) and in two dimensions (two first axes of the P.C.A.). The results of these treatments were confronted with the ground reference and thereby we conclude that this kind of treatments do not permit to distinguish the most important vegetal domains, for they are formed by the same associations of vegetal classes. This first observation lead us to perform a sequence of treatments based on textural features. Textural images of gradient (Sobel) were calculated, a local density of gradient was extracted by the convolution with a 7x7 scanning window, and this textural information was mixed with the reflectance one , on the same level, in a Bayesian classification. The choice of that sequence of treaments was conducted by the reflection that natural photography is interpreted by human vision, putting a hierarchy upon limits, the strong one upon reflectance limits, and at an inferior level upon the textural ones (reflectance ar rangement). Now, we saw that the main limits from the point of view of structural study of superficial formations were separating domains with the same associations of vegetal classes, giving the same visual impression of colour, but with different arran gement of classes which give a visual impression of different textures. The way of expressing textural information at the same level that reflectance one, makes images where the im portant limits are very visible, and which are very near to the map of vegetation repartition we obtained both by interpretation and by field s.udy. The two figures below are showing the interpretation of the natural photography (which can be compared with the map of vegetation, figure 3), and the image resulting of the sequence of treatments described. We can see that this image is nearer from the map than is the interpretation of natural photography. Figure 4 : Photo-interpretation of the natural photography Figure 5 : Image resulting of ¡he studied sequence of treatment 2 FRENCH GUYANA Fig. 1 shows the site under study. There, the granitic shield is covered with a clay-sandy material ('Sérié Détritique de Base' for geologists). Tropical forest covers the whole shield (more than 97% of this country area.) Studies made in Guyana by BOULET and al., starting from 1976 show that the initial ferrallitic cover, developped from the weathered shield, is now out of equilibrium and is therefore being transformed. The initial ferrallitic soil is tranformed here into podzol, and in geographical space, this transformation is more or less rapid; these transformations act at the scale of the existing topography, that is here about 1 km; and the transition between the ferrallitic pole and the podzolic one may be very short (100 m.) or may cover the whole watershed.

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