mA GAP S.» "CS 
  
Oyama, Yoichi 
3 PROBLEMATIC POINTS 
The matters found out by this study as to need further improvement are the following 3 points. 
1) Improvement of work efficiency to extract topographies and ground objects by analytical plotter 
2) Reduction of time used for the construction of maps 
3) Limitation of recognition by maps 
3.1 Improvement of work efficiency to extract topographies and ground objects by analytical plotter 
The operator of analytical plotter made plotting and measurement by a stereo model obtained from aerial photograph. 
Extraction was done by presuming the scope and height of surface only based on the alarm sound. As a result, there 
were some objects which were omitted in the course of extraction work, which were later found by site workers and 
from existing materials such as maps, and each time, it was necessary to repeat the measurement, calculation and site 
measurement using analytical plotter. 
3.2 Reduction of time used for the construction of maps 
We used long time for spatial treatment (patching up of screen tone) of sea surface and rivers. Also, far longer time than 
expected was necessary for the works to correct the shape of ground objects after the completion of spatial treatment. 
3.3 Limitation of the recognition by maps 
There was a limitation in grasping the three dimensional relation of position between topography / ground object and 
the surface only by the plans incorporating the heights and longitudinal section maps. 
4  PROPOSAL OF PLAN TO IMPROVE BY DIGITAL PROCESSING 
We attempted to solve the problems pointed out in the above by changing; 
1) Measurement by analytical plotter, and 
2) Construction of map by tracing 
to 
1) Measurement by digital photogrammetry system and 
2) Output of maps from CAD. 
5S CONCRETE METHOD OF EXPERIMENT 
1) A stereo model is made by inputting the picture image obtained by scanning of aerial photograph into the digital 
photogrammetry system. : 
2)Each surface is developed as 3-dimensional polygon on the CAD of digital photogrammetry system. 
3)While acquiring the normal 3 dimensional topographic data, a point is inputted to the highest position of the 
topographies and ground objects which are likely to contact the surface. Whether the object protrudes over the 
surface is judged by the operator from the positional relation with the surface already developed. 
4) The topographies acquired are edited by CAD, and sea areas, etc. are outputted after converted into polygons and 
placing hatching on it. 
5) The view from a side becomes the longitudinal section drawing in order to develop the topographies / ground objects 
and surface 3-demensionally using CAD. 
EI 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1099