LAS 
now- 
11s. 
ypes. 
srent 
ps 
li- 
Nn 
at- 
lass 
lass 
con- 
5 — 
atic 
est 
ma-- 
an 
uous 
per- 
cu- 
= 1804 - 
As in the visual interpretation, the supervised classification 
results in an overestimation of the total forest area. But 
- compared with the visual interpretations - opposed (and not 
sufficient) estimates have been obtained for the three "forest 
types". Surprisingly the deciduous forests were overestimated and 
the pine forest area, which could be clearly interpreted visually 
in the color composite, was considerably underestimated. 
Again one can conclude that, due to the available ground resolu- 
tion too many pixels ru ain mixed information which do not meet 
the spectral characteristics of the definite training areas of 
the selected types. Especially the pixels which mainly represent 
mixed forests have been preferably classified as deciduous forests 
and also many agricultural areas were mis-classified as deciduous 
forest. 
Table 6 illustrates the results from the second method of mapping 
accuracy estimation which used an overlay with a net of 1 x 1 cm 
squares for both, the ground truth and the computer map. This 
accuracy estimation results in a confusion table (table 6). 
Table 6 Confusion table used for test area 1 = Supervised 
  
  
  
classification 
Forest Test Test Squares Classified Correct Omission 
Tvpe Squares as Type Classified 
n 1 2 3 (4) n=% n=% 
pinus silv. 100 80 7 0 13 80 20 
deciduous 100 2 89 0 9 89 11 
mixed conifers 100 0 7 93 0 93 7 
unclassified 9 0-8 0 0 - = 
Commission E 2 14 0 22 - _ 
n=% 
Inventory 
result n 300 82 103 93 22 - - 
Deviation n -18. 3 -7 +22 — - 
Average accuracy performance in $ 87,33 - 
Analyzing table 6 it can be observed that deciduous stands were 
"confused" with the "class 4" (= unclassified areas) in 9% of 
the cases. This is mainly due to the spectral similarity among 
vineyards and grassland when compared with deciduous stands. This 
was especially evident in areas with rugged topography. 
With regard to mixed coniferous stands (class 3), the possibility 
of interpretation seems to be better than for deciduous. Even so, 
some "confusion" was also observed (7%), despite the distinct 
spectral signatures of both covers. This problem could have 
arisen during the ground truth preparation when some deciduous 
stands (considered small ones) were introduced into the coni-