Mroz, Marek 
  
Puszeza Biala forest. 
  
YEARS 
1 0-20 
5 21-60 
   
    
9 61-100 
  
  
13 > 100 
  
  
  
  
  
  
  
Meters Stand age map. 
PME n 
2,000.00 ] | 
1 
  
  
  
Figure 4. Stand age classes. 
3 PROCESSING AND INTERPRETATION OF SATELLITE IMAGES 
A SPOT-4 XS image from 19 September 1998 has been used in this project. Comparing to the three previous satellites 
from SPOT family, SPOT-4 has the capability to image Earth surface in the middle infrared band XS4 (1580-1750 
nm). Using red, near- infrared and middle infra-red bands the new images NDVI (Normalized Difference Vegetation 
Index) and NDWI (Normalized Difference Water Index) have been calculated. For visual interpretation of images many 
colour composites have been first created. We have realized that XS4 channel is strongly correlated with XS1 and XS2 
channels (r=0.9 and r=0.8 respectively). Nevertheless one can state that this channel brings quite interesting 
information on certain forest vegetation associations. Two chosen composites are shown below. See Fig. 5 and 6. 
It is clearly visible that the lines extracted from forest map and overlayed on both composites follow quite well the 
boundaries between different colours distinguished on the composites. We have realized that it is possible to interpret 
the composites as follows: 
On the both we can distinguish coniferous forest, (principally old, high pine forest) , mixed forest and deciduous wood. 
Particularly on the composite with NDVI component (not attached to this paper) we have found clear differentiation 
between alder forest and other mixed deciduous wood parcels. As one can see on the figures below using of XS4 
channel has showed the differentiation between young coniferous greenwood (less than 20 years) and old coniferous 
forest. In the next step for more precise description of the image usefulness for forest vegetation differentiation we 
have carried out some unsupervised classifications (clustering). The used algorithm has been the one implemented in 
IDRISI 2.0 package (ISOCLUST). Each classification has been executed in 3 iterations with 25 clusters at the 
beginning of the classification process. The results of clustering showed below are from three data sets: 
1... "A" XS3, XS2 and XS1 
2... "B" XS3, NDVI and XS1 
3 € XSA, XS3, XS2. 
The centers of initial clusters have been defined by the colours of appropriate colour composite. So, the results of 
clustering could be coherent (consistent ) with the visual interpretation of the colour composite. 
The clusters issued from this process have been carefully inspected, visually interpreted and statistically compared to 
the thematic layers extracted from forest sites map. Initially determined clusters have been logically aggregated in the 
groups which can be labeled as thematic classes with the high level of confidence. As auxiliary means for image 
interpretation and clusters labeling the aerial false-colour infrared photos at 1:10 000 have been used and terrain 
reconnaissance has been done. 
  
914 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 
Figure : 
  
Figure (