EXTRACTION OF LANDSLIDE AREAS USING MSS DATA AND THEMATIC 
MAP DATABASE SYSTEM 
M. Shikada, T. Kusaka and K. Miyakita 
Kanazawa Institute of Technology 
Nonoichi-machi Ishikawa 921, JAPAN 
ABSTRACT : 
The objective of this study is to extract areas where landslides may occur in the near future by using 
MSS data and thematic map data. Occurrences of landslides are considered to be closely related to 
vegetation, geologic and topographic features. 
We used an Image-Map database system based on digitized thematic maps related to landslides 
and NVI (Normalized Vegetation Index) data which was produced by MSS data. As a result, 
this analysis system shows that characteristic features in landslide areas can be extracted by using 
geology, inclination angles and NVI. 
KEY WORDS: Thematic map, Landslides, MSS data, NVI 
1. INTRODUCTION 
Satellite imagery has been used to clarify char- 
acteristic property of the ground surface by the 
advantage of broad area observation and period- 
icity [1]. 
Satellite data obtained from space has many ad- 
vantages. However, if we are going to get more 
useful results, it is necessary to combine satellite 
data and ancillary data. In this case, ancillary 
data implies the condition of ground surface and 
underground, map information and etc.. 
In this paper, we will first describe an advanced 
image analysis system using an image-map data- 
base system. This database is constructed by nu- 
merous thematic map data. Next, this analysis 
system will be applied to the Noto area in Japan 
where landslides generate in all season. And we 
will discuss the relationship among the angle of 
inclination, geology and elevation of landslide ar- 
eas. Then, NVI data corresponding to areas of 
landslides will be investigated. As a result, it 
is shown that characteristic features in landshde 
areas can be extracted by using the Image-map 
database system. 
2. DIGITIZATION OF THEMATIC MAPS 
AND DATABASE 
2.1 Thematic maps 
In this study, two types of map information are 
used for the landslide areas. One of them is con- 
cerned with the landslide, obtained from spot in- 
vestigation. The other one is Digital National 
Land Information (DNLI). DNLI consists of some 
information from the country [2]. 
Thematic maps prepared for this study are as fol- 
lows: 
(1) Investigation maps of landslides. 
(1:25000-scale map: investigated in 1986) 
(2) Geological map 
(ISHIKAWA prefecture:1:100000 scale-map) 
Dangerous zone maps on landslides were made 
mainly by the Ministry of Construction and 
Forestry Agency. The number of points land- 
slides already occurred in the past were about 
700 places (totaling about 290 km?). 
On the other hand, landslides which may occur 
in the near future are about 200 places (totaling 
80 km?). This data has high level of reliability. 
The geological map of ISHIKAWA prefecture was 
devided into 7 blocks. Each segment has 13 to 27 
types of geology which was painted with several 
colors for easy discrimination. 
2.2 Methodology of dizitization 
It is necessary to convert thematic map into digi- 
tal information because it is analogue data. In 
digitizing thematic maps, the Standard Local 
Area Mesh Code (SLAMC) which was used to 
DNLI, was adopted. The SLAMC consists of 
three groups of digital code, i.e., First Mesh (4 
digit numbers), Second mesh (2 digit numbers) 
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