2004 
etric 
ation 
ctral 
did 
hical 
sing 
phic 
iion 
TM 
apid 
the 
tal, 
ta et 
and 
ectra 
ts or 
ctral 
'ctra, 
Lor. 
)03). 
high 
tors, 
f the 
akes 
st 
uhas 
De 
easy 
nage 
erful 
e of 
ance 
main 
lem. 
the 
nage 
blem 
such 
and 
Is is 
d to 
lass. 
with 
es, it 
local 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 
variations in the spectral property of a surface become more 
apparent, such as humidity, elevation and shading effects 
(Gebbinck, 1998). 
2.5 Endmember selection 
Image endmember's for Landsat TM and Quickbird were 
selected through visualizing spectral scatter plots of image band 
combinations using ENVI system. A Principal Component (PC) 
transformation was used to guide image endmember selection 
since it puts almost 90% of the variances on the first two 
components and minimizes the influence of band to band 
correlation (Small, 2003, Wu and Murray, 2003). After 
examination of figures 2A and 2B, it is obvious that TM is 
spectrally richer than Quickbird. Important lithologies, as 
shown in the geological map (figure 1), such as the basic and 
acidic magmatic bodies and the iron caps are much more 
perceptible in the TM image. Quickbird does not have any 
spectral bands between 1.55 and 2.35 um and this area of the 
spectrum is essential for geological discrimination. 
As illustrated in figure 3A, a total of 8 endmembers were 
extracted. from the TM image such as basic and acidic 
magmatic rocks, iron caps, schists, carbonates, Quaternary 
deposits, sandy loams and finally vegetation. These 
endmembers were all significantly different from each other, 
thus could be used with confidence for classification. The 
carbonate endmember was selected in the TM image where it 
was observed in the field with GPS coordinates. For Quickbird 
(figure 3B), the same endmembers were chosen, but the 
carbonate unit was neglected because it had low separability 
with several other endmembers, which would have given bad 
results for the classification. 
  
  
  
  
601 
  
  
  
  
Figure 2 — PCA color composite for Landsat TM (A) and 
Quickbird (B) (PC 3 = Red, PC 2 = Green and PC 1 = Blue). 
  
Reflectance (%) 
  
  
N 
va 
4 5 6 7 
Landsat TM bands 
—$— Basic Intrusions —#— Acidic Intrusions 
Iron Caps Schist 
—*— Carbonate —+ Sandy loams 
—— Quaternary deposits Vegetation 
  
  
Reflectance (96) 
  
  
  
Quickbird bands 
—$*— Basic Intrusions —#— Acidic Intrusions 
Iron Caps Schist 
—s*— Sandy loams —^— Quaternary deposits 
—+— Vegetation 
Figure 3 — Endmembers for TM and Quickbird