Oyama, Yoichi
PRACTICAL APPLICATION OF DIGITAL MAPPING TECHNOLOGY
—CASE OF SPATIAL ANALYSIS BY 3D DIGITAL MAPPING—
Noboru Fukushima*,Yoichi Oyama*
* Photogrammetry Group Kokusai Kogyo Co., Ltd. Tokyo, JAPAN
noboru_fukushima@kke.co.jp, yoichi_oyama@kkc.co.jp
KEY WORDS: Digital Mapping, CAD, Limit Surface, Digital Photogrammetry System
ABSTRACT
The biggest advantage of digital mapping technology is said to be the flexibility in the expression of maps such as the
output at optional scale and of the optional items as well as the reproduction of maps. However, these are on the
extension line of conventional analog mapping technology and do not point to the essence of digital mapping. The real
worth of digital mapping can be said to be the utilization of digitalized 3 dimensional coordinates. So far, attempts have
been made to use the 3 dimensional data obtained by digital mapping for the applications of each field, and in fact, they
have been applied to the businesses in practice.
In this study, we discussed the method to extract the structures and topography which are protruding into the upper
space which has to be reserved, and to identify the extent of protrusion and the locations of these objects. The digital
mapping can be said, after all, to be the effective means to efficiently acquire the heights of scattering structures and
topographies.
In this paper, we will introduce the process of current study using the analytical plotter, and then report the procedures
by which we used the digital photogrammetry system in an attempt to solve the problems found out in the process of
current study. We will discuss the efficient study methods and new possibilities obtained from these results.
1 OUTLINE OF THE STUDY
1.1 Study area
We selected a middle sized city of 40 k ni including the surrounding areas which has mountains of 200 — 300 m in
height at its north east as the study area.
1.2 Objects of study
We assumed a virtual space above the study area and specified its lower limit surface. We formed the surface by
combining a surface which has inclinations along with the ground surface and a horizontal surface. We specified as the
study objects the tall building, towers and mountains having the value of Z coordinate which is higher than or close to
the lower limit surface.
1.3 Details of study
We used monochrome aerial photograph of 1 / 20,000 for the measurement. We measured and calculated study objects
having the highest altitude and the distance from the surface, and attempted to construct plans and longitudinal section
maps to identify those locations.
2 STUDY METHOD USING THE ANALYTICAL PLOTTER
2.1 Measurement by analytical plotter (judgment whether the object is protruding over the lower limit
surface)
It is necessary to acquire the accurate height of object protruding over the lower limit by the actual measurement at the
side. However, it is difficult to presume at the site whether the object concerned may contact with the virtual surface.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1097