Osman, A.R. 
  
3. MATERIALS AND METHODS 
Materials used were satellite images. Mirror stereoscopes, binoculars, tracing paper, drawing pens and light tables. 
The methodology used was the element interpretation used by LT.C. Enschede the Netherlands. For calculating the 
sinuosity index the formula of BRICE (1964) was used. 
SI- Length of channel 
Length of Meander Belt Axis 
Field check was done for about two month to find out the ground truth-along the Blue Nile. 
4. RESULT AND DISCUSSION 
4.1 Results: 
Brice (1964) used the sinuosity index to separate straight from sinuous and meandering channels. If the SI is less than 
1.05 the canal is straight, if SI is between 1.05-1.5 it is sinuous and if is higher than 1.5 the pattern is meandering. 
SI 105 = Straight 
1.05-1.5 Sinuous 
15 Meandering 
The equation from BRICE (1964) was used in our study area of the Blue Nile in the central plain of the Sudan. 
For map (A) the calculated sinuosity is 
447 — 2.21 Meander 
2.02 
For map (B) the calculated sinuosity is 
29.8 
20.4 
=1.44 Sinuous 
For map (C) the calculated sinuosity is 
274 =] 34 Sinuous 
20.6 
4.2 Discussion 
Geomorphologic interpretation on aerial photographs can be a direct interpretation because of the visibility of the 
objects. On the satellite images one has to use other criteria for the indetification of landforms. There is generally less 
deduction involved than on most other kinds of interpretation and a high degree of reliability may thus be obtained. The 
abilicability of the technology in geomorphological survey and mapping is obvious detailed maps in scales of up to 
1:50,000 can be made with the aid of large to medium scale aerial photographs (VERSTAPPEN 1977). 
An accurate, detailed and quick representation ofthe relief form is then insured and investigations can be carried out 
even if no reliable topographical maps of the area exist. Small-scale imagery such as that obtained at present from 
orbiting spacecraft can contribute for geomorphologic reconnaissance and mapping even at a scale of the order of 
1:1,000,000 and less. It is typical to our study case. 
Rivers are dynamic and important a part of the physical environment. They are essential agents of erosion and 
transportation. In performing their erosional and transportation work, rivers have developed and continue to develop a 
wide range of net works and channel forms. 
5. LANDFORM OF THE STUDY AREA 
The study area is characterized by fluvial landform. The fluvial systems have the energy to erode and transport large 
quantities of soil debris, sort, the materials and eventually deposits them. 
  
  
  
  
1090 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.