73 
After rasterization of DEM with resolution of lm pro x- 
and y-axis, the water flow analysis was performed and 
pits are identified and visualized (cyan color in Fig.5.). In 
hydrological sense pits hold water and disable it to flow 
over terrain continuously. So the artificial pits have to be 
eliminated from DEM especially if it was interpolated for 
hydrological purposes, too. 
Fig.5. The visualisation of DEM with pits identified. 
Fig.6. Pits with pitpaths 
A way to let a water flow out of pit is to ‘excavate’ a 
channel from pit base to outflow point and further to its 
adjacent down-stream basin. These pitpaths are in 
raster format originally and have to be converted into 
vector format (WINPUT) to make a possible to include 
it into the next interpolation as structure lines. 
With pitpaths as formlines the next interpolation of 
DEM was performed. As a result, the pitsfree DEM is 
produced, which showing the following result after 
contoruing (Fig. 7.) 
Fig. 7. Contours of test area after pits removal process.