1. Eastern Guiana shield land cover classification using
SPOT-4 / VEGETATION instrument
Gond Valéry
CIRAD, Natural forest department
Route de Montabo BP 165
F Cayenne
French Guiana
GLC 2000 – “FIRST RESULTS” WORKSHOP
JRC – Ispra, March 2002
Centre International
De Recherche en Agronomie
Pour le Développement

2. CONTEXT
An almost unknown area generally considered as a big green leaf
An heterogeneous continuum of forest (180 tree species by ha)
- A hot-spot of Biodiversity (1200 tree species in French Guiana)
An inaccessible fragile ecosystem (except by rivers)
A high cloud cover rate perturbing image analysis

3. General documentation of the area
Eva, 1999
Lowland dense moist forest
Coverted forest cover
Mangrove
Seasonally flooded grassland
Scolar book, 1999
Forest
Cerrado
Coastal forest
Siebert, 1996
Humid tropical forest, plaine
Open woodland, cerrado
Inunded tropical forest
Mangrove

4. First approach : angular study*
From -45° to -30° West
Nadir
From +30° to +45° East
Cloud mask inspired by Cherlet, et al., (2000) using B0 and SWIR
Empirical estimation of the cloud shadow (dilate filter around cloud)
Take into account of view angle using VZA
loss of information (eastern coast) because of the shadow mask
Mis-classification of pioneer front and forest class (confusion)
Patch effect over several places (mis-classification)
* In cooperation with Jousseaume, K.

5. Second approach : temporal classification
Basic cloud detection (BO > 50)
Ten-day composite based on maximum NDVI
Monthly composite based on minimum SWIR
ISODATA classification using B2, B3 and SWIR on 12 composites
Mis-classification of particular features (Brazilian fish-bone)
Mis-classification of inner savannas (South Surinam)
Cloud patterns in many places

6. Third approach : annual compositing1 2 3 4
Third approach : annual compositing
Forest
Savannas
Swamp
Belem
Agriculture
- Basic cloud detection (BO > 50)
Ten-day composite based on maximum NDVI
Monthly composite based on minimum SWIR
Annual composite based on minimum SWIR
ISODATA classification using B2, B3 and SWIR on the annual composite
Good elimination of clouds and partial elimination of shadows
Accuracy of features (fish-bones, savannas, agriculture)
Identification of specific area (inner forest gradient)

7. Validation : macro-analysis
Topography
Geology
Guiana shield coherence (topography
and geology)
Relationship with rainfall
Botanical coherence
Rainfall
Rain gradient
Botanical knowledge

8. Validation : high resolution images-analysis
Guyana-Suriname border
Rio Tocantins
Landsat +ETM
Forest limits
Agriculture polygons
Tumuc Humac Devide and savanna
Belém
Forest – savanna limit
Fragmented cover
Santarém transamazonian
Rio Paru and Rio Jari
Forest mixing
Hydrographic features

9. Validation : Counami forest1 4 2
5°21’58 N
53°12’52W
Wetland
5°24’6 N / 53°6’25 W
Savanna
Palm trees?
5°15’0 North / 53°8’2 West
5°8’34 North / 53°9’6 West
Illegal gold mining
5°17’40 North / 53° 17’8 West
Legal logging

10. Eastern Guyana shield land cover
5°South
46° West
7° N
59° West 0°
4°N
4° S
50° W
54° W
58° W
Forest (type1)
Forest (type 2)
Forest (type 3)
Inundated vegetation
Wetland, swamp
Converted forest
Savanna
Water, not classified N
100
200
300 km

11. Legend LCCS Inundated forest Broadleaf evergreen forest on
Permanently flooded land
Plain : Flat to almost flat
Sedimentary rock, sand
Podzols
Tropics – perhumid
Altitude <50m
LCCS code:
Legend LCCS
Forest (type 1)
Multi-layered broadleaf
Evergreen forest
Plain gently undulating
Metamorphic rock, shale
Ferrasols
Tropics – Perhumid
Altitude
No visible erosion
LCCS code:
Wetland
Broadleaf evergreen open woody veg
On permanently flooded land
Plain, Flat to almost flat
Sedimentary rock, clay
Gleysols
Tropics – perhumid
Altitude <50m
LCCS code:
Forest (type 2)
Multi-layered Semi-evergreen
Plateau gently undulating
Plutonic rock, granite
Ferrasols
Tropics – perhumid
Altitude
No visible erosion
LCCS code:
Converted forest
Scattered clustered fields of rainfed
Graminoids crops with isolated fields
Of broadleaf evergreen tree crops
Plain : flat to almost flat
Sedimentary rock, sand
Podzols
Tropics – perhumid
Altitude <50ml
Food crops
LCCS code: 10877
Forest (type 3)
Multi-layered semi-deciduous
Plateau gently undulating
Plutonic rock, granite
Ferrasols
Tropics – humid
Altitude
No visible erosion
LCCS code:
Savanna
Open medium tall grassland with
Medium shrubs
Plain : gently undulating
Plutonic rock, granite
Ferralsols
Tropics – humid
Altitude m
LCCS code:

12. Neccessary improvments
- Bad restitution of a pattern in North Para.
Is it a Forest type 3 or a Savanna?
Bad delineation
Bad restitution of two types of forest
Forest type 1 and 2 difficult to separate
Bad classification along Oyapock river.
There is only forest there, no lake.
Confusion coming from cloud shadow
- taking into account the shadow in the process