Reusing, Matthias 
- closed high forest 
- slightly degraded high forest 
- heavily degraded high forest 
After all data sets had been transferred to a digital format, a spatial overlay analysis was performed. During this process, 
the older classification results were compared with more actual data sets in order to detect changes. All technical 
procedures were realised with the commercial software products ARC/INFO, ArcView and IDRISI for Windows. 
  
FOREST-MONITORING IN ETHIOPIA 
GIS-Data Processing 
  
HISTORICAL DATA ACTUAL DATA 
- analogue - - digital / Vector Format - 
Satellite Image Interpretation Satellite Image Interpretation Satellite Image Interpretation 
LANDSAT-TM Data LANDSAT-TM Data LANDSAT-TM Data 
from 1973 to 1976 from 1986 to 1989 from 1986 to 1990 
(FAO/U NDP, 1986) (W BISPP, 1997) (ABAY, 1997) 
  
  
  
  
  
  
Digitize & Create Topology 
in ARC/INFO 
| 
Forest Cover 
1973 to 1976 
- Vector Format - 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Import to IDRISI Import to IDRISI Import to IDRISI 
| | 
SQL-Selection SQL Selection 
1 1 
Forest Cover Forest Cover 
1986 to 1989 1986 to 1990 
- Vector Format - - Vector Format - 
Vector/Raster Conversion Vector/Raster Conversion Vector/Raster Conversion 
Merging/Appending e d 
  
  
  
Forest Cover Forest Cover 
1973 to 1976 1986 to 1990 
- Raster-F ormat - - Raster-F ormat - 
  
  
  
  
  
  
a Additive Overlay Analysis ee 
FOREST MONITORING 
1973 to 1990 
  
  
  
  
| 
MAPS & STATISTICS 
| 
End-Users: Planners & Decision-Makers 
  
  
  
Figure 1. Flowchart of remote sensing data and main FIS analysis procedures 
3 DATA ANALYSIS 
3.1 Forest degradation in Ethiopia between 1973 and 1990 
The historical data set was based on a visual interpretation of 71 analogue LANDSAT/MSS satellite images, which 
were recorded between 1973 and 1976. The resulting land cover maps in scale 1:1,000,000 show closed and slightly 
degraded forest areas of different vegetation strata (FAO/UNDP, 1978). According to this data set 6.08 % of the 
country's area, respectively 69,599 sqkm was still stocked with natural high forests in the seventieth. 
  
1254 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.