Jeyapalan, Kandiah 
  
Total Station coordinates to the WGS GPS coordinates, two 
calibration points on the total station traverse were established from 
GPS control station using two Trimble 4000 SSI GPS survey unit. 
As in WA-1, the GIS map using Arc/Info was produced from the 
Autocad drawing file drawn from the date collector data. 
OR-3 is in the Metropolitan area. DGPS is not accurate enough for 
mapping at a scale of 1"— 25' and further cannot be used because of 
the obstruction of signals by tall buildings ( Fig 4). Therefore Total 
station methods were adopted. Further, because of the tall buildings 
calibration points using GPS were established outside the area 
which resulted in a long Total Station traverse. Fig. 5 shows the GIS 
map. 
   
   
  
Fig 3. Winding Road 
  
Comparison o Ai amd wäh ground Trab 
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Fig 4. Tall Buildings Fig 5. GIS Map 
VIDEOLOGGING 
With the advent of video and digital cameras videologging of roadside features have become part of the state wide 
transportation data collecting system. 
By having a van equipped with a video camera whose triggering system is controlled by GPS receiver, it is possible to 
get a video image and also its location. Fig 6 shows the Mandli Cooperation Videologging system which was used in 
this study. The system was also equipped with Inertial Navigation System, which substitutes for GPS location 
whenever GPS loses lock due to signal obstruction. 
This ensures continuous position determination. 
In most inventory studies the location of features along 
the center line are sufficient. Therefore feature 
locations were interpolated from the average distance 
between photos. Figure 7 shows the comparisons of 
videologging with ground survey by DGPS and Fig 5 
with Total Station. 
In order to check the quality of video images and the 
accuracy of GPS locations of the video images a test 
range was established see fig 8. This test range 
represents a typical road section. It is a relatively flat 
Fig 6. Videologging section of road 100ft in length with pavement 
markings, street signs and reflectors that are used for 
  
  
408 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000.