and consumed about 50 MB storage space. The 
following figure shows the DTM generation process. 
  
  
    
  
         
  
=I ae ^ NY 
f EN s TEN EN 
TN WA cn t y. M uot Z^ 
N Aa N ~ N oH oy \: 5 |: x 
{QS SES == N al N 
LUE SEE ST Se 
   
    
    
   
  
  
ud 
vs pere EC 
Pc hs 
    
  
   
  
  
  
Te 
= 
  
Figure 4 Part of the generated TINs for the study 
area. 
Identification Process 
The overlay and buffering functions were used to 
identify and map the developable land. The steps 
may be summarized as follows: 
* Generate TIN-DTM for the entire area. 
* Create slope map of « 20 degrees. 
* Create coverage polygon of the selected slope 
area. 
* Create coverage polygon of the selected criteria 
i.e. polygon of built-up area, polygon of 
reserved forest, and polygon of existing 
recreational and tourist areas. 
* Perform the buffering for the areas based on 
selected criteria. Table below shows the 
buffering parameters. 
  
  
  
  
Buffer 
Criteria layer distance 
(m) 
Built-up area 2000 
Leisure area (e.g. golf field) 3000 
Historical and tourist site 1000 
  
  
  
  
* Perform the overlay operations using the 
generated polygons of the selected criteria to 
identify the land, see Figure 5. 
RESULTS AND DISCUSSION 
Figure 6 shows the map of a suitable land for 
development in the study area. The study shows 
that the identification of developable land can be 
achieved quite straight forward using TIN-based 
DTMs and some overlay operations. The criteria 
selected influenced the mapping of the developable 
land. In this project, based on the selected criteria, 
local authority can visualized the potential land for 
development. 
REFERENCES 
Alias, A. R., 1992, Triangular Irregular Network in 
Digital Terrain Relief Modelling, M. Sc. thesis, ITC, 
Enschede, The Netherlands. 
Huber, M. 1995, Contour-to-DEM: A New 
Algorithm for Contour Line Interpolation, Joint 
European Conference and Exhibition on 
Geographical Information Proceedings, The Hague, 
Holland, Vol. 1, pp. 221-222. 
Kumler, M. P., 1994, An Intensive Comparison of 
Triangulated Irregular Networks (TINs) and Digital 
Elevation Models (DEMs), Cartographica, Vol. 31, 
No. 2. 
Peucker, T. K., Fowler R. J. , Little J. J., and Mark D. 
M., 1978, The Triangulated Irregular Network, 
American Society for Photogrammetry (ASP) 
Proceedings of DTM Symposium, St. Louis, MS, 
USA. pp. 24-31 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996 
  
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