STUDY OF GEOGRAPHICAL INFORMATION SYSTEM TO RENEW THE LANDSLIDE DISTRIBUTION 
Takayuki Inomata, Masahiro Setojima 
KOKUSAI KOGYO Co., 
Ltd. 
Asahigaoka 3-6-1 
Hino-City, 
Tokyo, 
Japan 
Commission No. IV 
ABSTRACT: 
Geographical Information System (G.I.S.) is 
in Japan, landslides 
landslides, it is 
often affect vegetation 
necessary to manage, 
good 
distribution. In Most cases, Land slides are caused by geological and geographical factors. 
and landuse. 
analyze and evaluate these kinds of 
the landslide 
Furthermore, 
renewing distribution of 
information. A map that 
for  renewing information of 
Therefore, in 
describe above results can support the renewal of landslides distribution. This study examines the use of 
G.I.S. for the renewal of landslide distribution. 
KEYWORDS: Extraction, GIS, Landslide, Overlay, Renew 
1. Introduction 
In Japan, landslide disasters have exerted 
influences on the livelihood of 
because landslides have occurred in large 
scale. The landslide which occurred at Mt. Zizuki, 
Nagano City, Nagano Pref. is a good example of 
large scaled disaster in recent years in Japan. The 
significant 
people, 
western region of Joetsu City of Niigata Pref. 
which we selected as the object area of our present 
study is a place where the landslides occur 
frequently, and therefore, it is necessary to 
always grasp the up-to-date information concerning 
the landslide distribution in this area. 
The information concerning the landslide 
distribution has been so far acquired as a result 
of air photograph interpretation and 
exploration/observation at actual sites. However, 
much time and labor are necessary to grasp the 
distribution of landslide because it expands over a 
wide area. In addition, the skill of high level is 
required for acquiring the information of landslide 
distribution such as: in, for an example, air 
photograph interpretation. This was the reason why 
much time and labor have been necessitated for 
collecting the landslide distribution information 
over a wide area at the same level of accuracy. 
Under such circumstances, the authors have been 
discussing the application of Geographical 
Information System (GIS) to the acquisition and 
renewing landslide distribution information 
(Setojima et al., 1991). Especially noteworthy is 
the utilization of GIS taking advantage of overlay 
function, etc. in order to improve the efficiency 
and uniformity of accuracy which have been major 
concerns in acquiring of landslide distribution in 
the past. 
The distribution of landslide is considered to 
be deeply’ related: to the factors sueh as the 
geological feature and the soil mechanics feature. 
In many cases, on the other hand, the landslide 
have exerted an influence on the various phenomena 
on land such as land use and vegetation. Therefore, 
it is necessary to discuss these pieces information 
one by one in order to renew the distribution 
information of landslide. But the efficiency of 
analysis will be enhanced integrating other various 
factors and making judgment basing thereon. GIS has 
various kinds of information in its database. Also, 
it. is possible for us to utilize the analysis 
function and spatial operation function of GIS for 
supporting the intended analysis. Therefore, it is 
considered effective to use the GIS for renewing 
the distribution information of landslide. 
We select the area at the western part of Joetsu 
City, Niigata Pref. 1 our study area. 
(Fig. 1) as 
This is a region where landslide took place 
  
0  150km 
Ea 
    
    
     
   
  
   
    
The Sea 
of Japan 
Sado/ls. 
The Pacific 
  
  
s Ocean vl 
\ 
) 20km Niigata Met 
\ 
= 
Study area JAN | 
N eS fw 
OR ME o 
run de L^ 
™ y^ y Nagano precis Carine Pref. 
/ / 
  
  
  
Fig.1 Study area 
frequently from the olden times (Akahane et at. 
1989). In 1963, railway disaster occurred in this 
region. due to a landslide. It. can be said, 
therefore, that this is the region where up-to-date 
information of landslide distribution should be 
grasped correctly. However, only the available 
information source of landslide distribution for 
this area is the landslide distribution map (at a 
scale 1:50000) which was made in 1969, and it is 
required, for this reason, to renew the information 
of landslide information in this region. 
In this study, we make analysis by using only 
the information which has been arranged as the 
plane information as much as possible in supporting 
the renewal of landslide distribution information 
(in case of the analysis on landslide, the 
existence of plane of slip and soil mechanics 
factors such as cé are important; these are 
detailed and point information, but we did not use 
them because they are not arranged as the plane 
information). Now therefore, the authors 
constructed a database using  planely arranged 
geographical information such as the distribution 
of landslides occurred already, topography (digital 
terrain model, DTM), geology and land use. Next, 
the authors overlaid the landslide distribution and 
geographical information and analyzed the 
relationship between them. Basing on this analysis 
result, the authors attempted the extraction of 
landslide areas, and used the information obtained 
therefrom as the basic information for supporting 
the renewal of landslide distribution information 
to be done on later stages. 
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