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Proceedings International Workshop on Mobile Mapping Technology
Li, Rongxing

Toshiaki Taguchi, Kosuke Tsuru
Air & Space photogrammetry Office, Aero Asahi Co.
Hirofumi Chikatsu
Faculty of Science and Engineering
Tokyo Denki University
Commission V, Working Group V/I
KEY WORDS: Digital Mapping, Field Investigation, DGPS, TIN-Model, Geometric Correction
It has been already passed more than ten years since the digital mapping started in Japan. During this period, the system was improved
so as to construct the fundamental system in the development of data structurelization and transformation of traditional mapping into the
standard digital mapping. However, these processes are just only the later half of the whole process of digital mapping. Hereafter, it
becomes necessary to digitalize process of leveling, control point survey and field reconnaissance survey etc. Especially in the case of
field investigation, almost all expressions concerning the Digital Mapping are included in the investigation results. So, if these
investigation results can be directly matched with digital mapping, the system to create Digital Mapping will be much more efficient.
In the present paper, the system to collect the field by using laptop computer with FM wave D-GPS system is installed is explained.
This system puts points of air photograph’s image data on same points of ground coordinates measured by D-GPS using differential
information service by FM multi-channel broadcasting. This system generates TIN-model from these points and image is geometrically
corrected by each triangle. So, it is able to improve positional precision of image without orthoprojector or results of aerial triangle
survey. And, the results of field investigations are digitized on these images. Operators can input map symbols or cartographic notations
directly and DM data can be checked with field investigation results without compare with aerial photographs.
Also, we tried the method to acquiring the coordinates of the objects that were not shown on the aerial photographs.
Usually, operators get mapping data with precious position using
stereo photo model to create DM (Digital Mapping). This process
called as plotting is carried out in a room. But it’s impossible to
acquire all of DM data using only photographs. Following data
are necessary to investigate on the field.
( 1 ) Objects which is hidden in shadow.
( 2 ) Objects which is difficult to specify by photo-interpretation.
( 3 ) Symbols for building classification or vegitation
(4 ) Cartographic notations.
In formerly field investigation, first, it is necessary to remake
photographs on same scale of final result map. Next, field
surveyors go to field and draw reconnaissance result on remade
photographs with ink pen. (Figure 1)
But, this method has some weak points.
( 1 ) Because field surveyors draw results on photographs, it is
difficult to correct mistakes. Also, ink is sometimes blotted
influenced by sweat or rain.
( 2 ) Operators refer field reconnaissance results on plotting or
editing. On this time, it takes much labor to match DM data
with remade photographs. (Figure 2)
( 3 ) Sometimes results aren’t inputted on DM data.
(4 ) It is troublesome to carry or to store remade photographs
after field reconnaissance survey.
On the other hand, if these field investigation results can be
matched with digital mapping process, the system for creating
Digital Mapping will be much more efficient.
Figure 1 Former Field Investigation Photographs
In this method, first digital image data of field are prepared
instead of remaking photographs. Next, field surveyors go to field
with laptop computer and GPS receiver. Then, digital image is
geometric corrected on field.