International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
Limitation in the method of aerial measurement:
In the construction of spatial data at the level of 1 / 500, it has
become clear that there are many areas where the photographic
mapping cannot be applied, the role of supplemental site survey
becomes high as a result, and it is difficult to construct the data
because the processes of aerial measurement and site
measurement are repeated in a complicated manner.
Limitation of GPS survey:
The methods such as RTK and VRS of GSP are expected to
provide prompt measurement of many unknown points and
improve the efficiency, but the measurement is made mainly by
TS because the applicable scope of GSP is very small in the
urban area due to the influence of surrounding structures. It is
therefore difficult to take advantage of the superiority of GPS in
the urban area.
Necessity of side survey:
In constructing the spatial data, it is necessary to investigate the
attributes that the ground structures have, and therefore, it is
necessary to implement the site investigation all over the
subject area. If any omission is found to the investigation, it is
inevitable to make re-investigation, and if the number of data
confirmation increases, the cost will be come higher as a matter
of course.
1.3 Development policy and expected effect
In order to solve the issues stated in the above, we aim to
construct the spatial data generation system by adding mobile
mapping technology to aerial photograph survey technique and
ground survey technique. There is a tendency as its background
that free conception is required to reduce the cost, improve the
quality and enhance the added value. Namely, it is required to
select the method according to the degree of quality required for
each ground structure instead of seeking for high precision
uniformly regardless of the objects. This is based on the notion
to place importance on the quality as the cost performance will
not be preferable if the method is limited.
The effects expected to the mobile mapping technology are as
follows.
(1) Role as the supplemental data to aerial photograph
This technology has the role of supplemental data to aerial
photograph by measuring from the ground the objects
concealed by forest or high bridge in the aerial photograph.
(2) Improvement of efficiency of ground survey
GPS has problem in use at urban area if it is used alone, but it is
possible to acquire continuous position information by
integrating it with IMU of automatic navigation system. And
therefore, it is possible to improve the efficiency of ground
work which is one of the issues of TS survey.
(3) Reduction of site complementary survey
The reproducibility of the site can be easily maintained by
recording the situation of site in detail, and the cost of
investigation will be reduced as the re-investigation of site is
avoided.
As stated in the above, it is possible to widely reduce the
production processes and production cost of spatial data by
developing the mobile mapping technology.
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2. OUTLINE OF SPATIAL DATA ACQUIRED
2.1 Structure of spatial data
The spatial data to be acquired is defined by the data
specifications conforming to the international standard (ISO /
RC211) and has the basic structure as shown in Figure 2-1.
Ground structure on or
inside the road surface or
road structure.
ifity Ex.: Road sign, lighting
facility, side ditch
Road surface
indicator
Road si
/
itch
Tree pit Ave wit of the toad surface
j (continuous plane).
Ex. Drive way, sidewalk,
shoulder
Ground structure installed to
support the road structures and
maintain the function.
Figure 2-1: Basic structure of spatial data
2.2 Information about the acquisition of spatial data
Acquisition information of spatial data is the following attribute
information.
Spatial attribute:
Indicating the coordinates and shape of ground structure
Thematic attribute: i
Indicating the type of ground structure
Temporal attribute:
Date of construction, etc.
Besides the above, there are definitions about the relation
among the ground structures. Since the lighting equipment,
signal and sign are added on the pole shown in Figure 2-2, there
is a relation between these ground structure and the pole, and
therefore, it is necessary to acquire the information about such
relation.
[17600
\ Csignal
Figure 2-2: Example of relationship among the ground
structures (pole)
es)
2.3 Measuring accuracy of spatial data
The measuring accuracy of spatial data is as follows (Figure 2-
1).
(1) 25 em or less (accuracy at the level of 1 / 500) in case of the
border line of ground structure (edge of road or sidewalk, edge
de structure Consisting
n A
XE
Ex.: Road bridge, tunnel "
Interna
of road sh
the area
(2) 70 em
the faciliti
The accur
specified
Land, Inf
3.
The condi
of mobile
3.1 Conc
(1) Study
The study
multi-leve
concealed
Therefore.
(2) Speed
In the gen
on the ca
crossing «
made whi
shooting «
the shuttei
3.2 Requ
(1) Scope
The spatia
shown in
must be m
Ground
the head
Signal pe
Road inf
Each ty
etc.
Ground
Road su
Figure
(2) Maint
As stated
1) 25 cm |
as the edg
2) 70 em «
as telepho
