601 
10 times magnifi- 
Lve photomorphic 
=d in detail on 
tographs were stu- 
the zoom-transfer 
:s in the desert 
rations and the 
rerent physiegtra- 
V7^A t6 (Mile Valley) UTHl 251/7(263) 
m nu) □ 263 
different erosio- 
rhe different docu- 
1 erosion process 
>attern. Multista- 
ilize the belts of 
:d limestone pla- 
U r 7\ (Nile /alley) 
i6,f-<n.X,H,? 
HI 263/189,c.Y.h,? 
3/189,c.Y.h.P 
ŒC53 189-263, c,Y,h,P/b 
STÀI 3/4,m-c,Y,h,P/b 
5~gl V263,.u,Y,h,P 
189-263/4.m-f,Y,h,?/b 
CH3 263.f.Y,h,P/b 
Fig. 3 - Multistage analysis of a sand dune zone 
A. Macro photomorphic units 
3. Micro pnotomorphic units 
C. Aerial photo interpretation 
0. An aerial photograpn or* a sand dune belt (scale 1:40,000) 
HI 12(263) 
ÜQJ -(263) ( ! 89) 
)/?89,¡n-c,Y,h,P/b 
!63,f ,Y,H,b 
¡/263-134,ra,Y,h,b 
ilysis of a sand sheet zone, 
imorphic units 
morphic units 
:o interpretation 
Low elevatea area (sanay 
1' A Mile Valley 
4.1.1 Sand sheet area 
This landform is visible on the colour composites, 
just west of the Nile Delta and along the northern 
part of the Nile Valley. The Macro-photomorphic units 
(fig. 2a) are characterized by bright coloured wide 
patches. The field investigation indicates that some 
parts, within this area, are covered by gravel and 
pebble deposits rather than by sand. It was found 
also that the deposits are characterized by the alter 
nation of layers (1-2 cm) of medium to fine sand and 
gravel. The subtle colour differences, appeared in 
the micro-photomorphic level(fig. 2B), may represent 
differences in size, spacing and composition of pebble 
deposits (El-Baz and Maxwell 1979). 
The aerial photo-interpretation of a representative 
area of sand sheet (fig. 2C) made it possible to see 
that it is characterized by an undulating topography. 
It was also possible to follow tne weax drainage pat 
tern in the rocky surface, which is controlled by NW 
SE direction. That direction corresponds to the NW 
SE direction of the fractures and the faults(Said 
1962). 
4.1.2 Sand dune belts 
This physiographic unit was observed in the macropho- 
tomorphic unit level interpretation on the colour 
composite (fig.3A) as a light coloured area (e.g. 
bluish white, mixed with light purplish pink). The 
microphotomorphic level subdivided this area into 
smaller units of different colour shades (fig. 3B). 
The interpretation of that area on a scale 1:100,000 
(fig. 3C) revealed the individual longtudinal dunes 
and the interdunes, and made it possible to estimate 
its morphometry and to see that the main direction of 
the moving dunes is S-N, which corresponds to the main 
wind direction. Although the resolution of the land- 
sat images is too small to detect the barghan dunes, 
it was noticed that the linear pattern of the long 
tudinal dunes takes a rounded shape, with a light 
colour in the lee-ward of some individual dunes. The 
detailed study of aerial photographs (fig. 3D) re 
vealed the existence of the barghans among the long 
tudinal dunes 
It was also possible to see that the barghans are 
moving in a North-South direction with some defla 
tion, having a West-East direction. 
4.1.3 The plateau 
The Western desert, in general, is a north-dipping 
plateau of sedimentary rocks. That rocky terrain 
appears on the landsat images as dark coloured macro- 
photomorphic units (fig. 4A). The interpretation on 
micro-photomorphic level subdivided the macro-photo 
morphic units into different shades (fig. 4B). 
These shades could be 
â ■ A. Macro photomorphic units 
4 v* " 4 if LUMI II I î I 
attributed to the impor 
tance of local bedrock 
outcrops, and stages of 
erosion. Multistage - 
interpretation defined 
the dark coloured areas 
as individual patterns 
and as composite patchy 
patterns. The patchy 
pattern is controlled 
by the existence of the 
light coloured eolian 
deposits. The indivi 
dual dark patterns occur 
where a single hill or 
□ 3 çj^rpmountain exists. It was 
Micro phoVo’ri™^? also possible to detect 
the very faint main 
drainage patterns on the 
landsat images. On the 
aerial photographs the 
small tributaries could 
be seen (fig 3D). The 
drainage pattern is 
dendritic and has a 
lighter colour compared 
with the surrounding 
hills. It was believed 
that these drainage pat 
terns indicate the flu 
vial processes during 
the pleistocene, which 
S3 ) 85-263/4 ,m-r,Y,h,F/b 
IS~5~1 3/4,nt-c,Y,h,P/b 
PTC) i2,m.):,)„P/i> 
Multistage analysis of a plateau area.