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ES E Falling Polles imulate
Air- Analytical Debris
Photograph Plotter
Figure 1.Flow Chart of This Study
of the wooden building is a middle degree. The degree
of damage was very big. This area is apart from
epicenter by 14 km.
b. Hyougo area
The town and the habitation area are contained in this
area. The percentage of the wooden building is high.
The degree of damage was very big. This area is
apart from epicenter by 16 km.
c. Sannomiya area
This is area of commercial center. The percentage of
the wooden building is low. The degree of damage
was big. This area is apart from the epicenter by 20
km.
d. Kasuganomichi area
This area is a dwelling center. The wooden
percentage of the building is high. The degree of
damage was light. This area is apart from the
epicenter by 22 km.
e. Rokkoumichi area
As for this area, the downtown and the habitation area
are intermingled. The percentage of the wooden
building is ordinary. The degree of being suffered was
big. This area is apart from the epicenter by 25 km.
f. Uozaki area
It is an area of the habitation center. The percentage
of the wooden building is high. The degree of being
suffered was very big. This area is apart from the
epicenter by 28 km.
g. Ashiya area
Itis a habitation area. The percentage of the wooden
building is high. The degree of being suffered was
light. This area is apart from the epicenter by 32 km.
2. 2. Construction of a data base
The authors acquired the following data and built a data
base.
1)Structure of street (width of street and walkway)
2)Debris and Falling poles (such as electric pole, signal,
streetside tree etc.)
3)Street network
<Measurement of the structure of the street>
Width of street was measured from the air-photograph
using the analytical plotter. The distance between the
intersections was determined as one link. The
narrowest portion in a link was employed as the width of
the link. That is because, the passage possibility of the
link is determined by the condition of the narrowest
width part. Also, when examining dysfunction at the
street, we need the width of the driveway. Therefore, the
authors measured the width of the walkway together
with the data of the street section.
<Measurement of the falling poles and debris>
Measurement was done using the air-photograph which
was taken after the earthquake. The air-photograph was
taken on next day of the earthquake, January 18th,
1995. The air-photograph used was vertical
photographs at the scale of 1/5,000. Photograph was
also taken immediately after the earthquake, on
January 17th, but there was a possibility to lead to a
fault in the air-photograph interpretation because of the
smoke by fire etc, and we didn't use for the
measurement. The falling of poles was measured in 3
dimensional coordinates at the root and the head of
poles using the analytical plotters. The blockade
percentage of the street was calculated from this
measurement value and the width of street. We
employed the debris which protruded over the road
because ofthe collapse of houses, etc. for the objects of
our study. The measurement was made to determine
the percentage of debris blockade over the road. As for
the measuring method, we used the interpretation by
analytical plotter and visual interpretation of air-
photograph enlarged by 5 times. The measurement was
represented by the part having the highest blockade
ratio among each link.
«Construction of a street network»
A street network was made from the city planning map
(scale 1:2500) published by municipalities using the
digitizer, and inputting a street centerline to it.
Incidentally, in the time used for data acquisition is as
follows. The number of link is 400 on the average in one
area.
A) Measurement of street width by analytical plotter :
1day for 1 area by one professional operator
B) Measurement of falling poles by analytical plotter :
1day for 1 area by one professional operator
C) Measurement of debris : 1day per 1 area by pair of
operators
D) Construction of network data : half day per 1 area
by one operator
2. 3. Integration of the data base
Acquired digital data was introduced to GIS. The structure
of the street and the situation of the blockade were
combined with the link of the network and used for the
analysis. Before data acquisition, peculiar ID gave to the
street link to provide the consistency among the data.
ARC/INFO(ver7.03) was used on SparcStation(Sun-4/10)
379
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996