Data On Nov.11, 1987; Landsat TM were 
selected for the research, because of the absence of 
cloud cover, channel data quality and time period 
most favorable to vegetation classification. The other 
kind of data are topographical maps (scale of 1 : 
50000 and 25000), geological and hydrological 
maps, the field investegation data. The SPOT data 
has a better spatial resolution than Landsat, so SPOT 
images would be more suitable to establish an 
engineering data base, but at the time no SPOT 
images of the test area were available. A second 
reason is that SPOT image is very expensive and very 
difficult to get. 
The hardware IMCO — 1000 Image processor 
incorporate a high performance programmable 
microprocessor and a large random access dynamic 
memory (up to 512 Mbytes for image plus 512 Mbits 
for graphics from KONTRON  Bildanalyse. The 
software (Geo-Jars) is a package of image processing 
and analysis for remote sensing applications developed 
by MICROM E SPANA, and designed for use on 
IMCO 1000 image processor. 
METHOD OF DATA PREPROCESSING 
Various data required for GIS were preprocessed 
as follows, block diagram of data preprocessing is 
shown in Fig. 1. 
l. Digitizing existing topographic maps (scale 1 
: 50000 and 1 : 25000) by DK2436 table digitizer, 
generate a digital terrain modle (DTM) to store in this 
system. The contour map; slope map; aspect map; 
relief shade map; 3D- perspective map were derived 
from the DTM to use for railway design. 
2. Geological and hydrological map get from 
digitized existing geological map hydrological map and 
some field investegate data. A conplex pacel structure 
are used. 
3. Feature extraction from the TM data was 
carried out. Selecting useful information for railway 
design, eliminating redundant information, removing 
uncorrect information. A house and artificial building 
map; water and road system map are got from the 
feature extraction procedure. 
INPUT DATA PROCESSING OUTPUT 
  
  
Engineering Database 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Existing Map Digitizer Report 
Tap Driver 'Table 
CCT 1600/6250 IMCO — 1000 
Image processor 
Field Data Key Board Film 
Digital Ma 
D 
Photo Camera 
  
  
  
  
  
  
Fig. 1. Flow Diagram of Data Processing 
736 
or te OY r3 r3