Establishing Spatial Database for Slope Failure
with GPS Digital Camera
Yuta YAMAMOTO, Jong-Hyeok JEONG, and Masataka TAKAGIInfrastructure Systems Engineering, Kochi University of Technology

ABSTRACT: GIS (Geographical Information System) is one of useful tools for disaster prevention.
Especially Web GIS based on Internet is a reliable system to collect information of many maps and theattribute data. And Web GIS will be very effective to exchange information. Therefore, the disasterprevention system with Web GIS is required.
The target of this study is to establish a system for collecting GIS data by using GPS digital camera. Theimage of GPS digital camera contains the coordinate of latitude and longitude in EXIF data. GIS data can beestablished by using the coordinate. However, the coordinate is just position of camera. The coordinate
should be converted to point of the object in the taken image. Moreover, disaster area should be mapped on
GIS.
In this study, converting method for coordinate of the object in GPS camera image will be developed using
Digital Surface Model (15 meters grid). The skyline image on the camera point can be simulated using DSM.
Direction of the camera can be calculated by image matching with the skyline. After that, disaster area will
be mapped .
Field surveying with GPS digital camera was carried out for verification of this system. The correct ratio ofskyline matching showed about 45%. A incorrect reason might be come from simple shape of skyline.
Correct ratio may be raised by using high resolution DSM.
In future, correct ratio must be raised, and shape of slope disaster in taken picture is generated as GIS data.
KEY WORDS: Web GIS, GPS Digital Camera, Slope Disaster
1. BACKGROUND

The coordinate can be stored in GIS data. However,

GIS(Geographical Information System) is one of

the coordinate is just position of camera, which isuseful tools for disaster prevention. Especially Webview point. The coordinate should be converted to

GIS is a reliable system to collect information of

actual location information of slope failure area.

many maps and the attribute data. And Web GIS will
be very effective to exchange information. Therefore,
the disaster prevention system with Web GIS isrequired.
Now image database on slope failure is establishingby using GPS digital camera. Mapserver is used tointegrate database. The Mapserver was launched forWeb GIS. The Mapserver was developed byMinnesota University, which is freeware. The GPScamera can take a coordinate of the place of camera.

Figure1: Outline of Web GIS

Table1: Specification of GPS Digital Camera

2. OBJECTIVE
In this study, spatial database of slope failure withGPS camera will be established. Firstly, system forobject point calculation from view point of GPScamera will be developed. Next, slope failure area inSpecification of Digital Camera（RICOH RDC-i700）
Model Number

RDC-i700

Specification of Imaging Element

3.34Mega Pixel

File Format

Compress：JPEG（Exif2.1）

Specification of GPSReceiver（I-O DATA CFGPS2）
Model Number

CFGPS2

camera image will be converted as GIS data. Figure2

Frequency of Receive

1575.42MHz（C/A code）

Formula of Receive

Multi Channel（12Channel）

showed general idea of generating GIS data fromAccurasy of Receive

below -140dBm

shape of disaster in image. Finally, this system will
be evaluated by field surveying.

Land Surveying/A Coordinate System

Tokyo, WGS-84

Accuracy of Pinpointing

below 10m（2DRMS、SA OFF）

Accuracy of Speed

0.2m/sec(SA OFF）

4. METHODOROGY
4.1 Concept of Converting Method by Skyline
Matching
Figure4 showed flowchart in this study. Convert
system for shape of slope failure area in GPS digital
camera image will be developed using skyline
matching. The skyline simulation image at the view
point can be generated using Digital Surface Model(DSM). DSM is one kind of elevation data including
Figure2: General Idea of Generating GIS Databuildings or trees, which can be generated byfrom Shape of Disaster in Imagesatellite data or aerial photograph. Direction of thecamera can be calculated by image matching3.

SPECIFICATIONOFGPSDIGITAL

between extracted skyline from GPS camera image

CAMERAand the simulated skyline. After calculating view

The image of GPS digital camera contains thedirection, GIS data of slope failure area in the image

coordinate of latitude and longitude in EXIF data.

can be generated by intersection on DSM and theFigure3 and Table1 showed the appearance and thevector from slope failure area in the image.

specification of GPS digital camera in this study.

Figure3: GPS Digital Camera

Figure4: Flowchart4.2 Simulation Image of Skyline Using DSM

cylindrical projection. The center of projection wasFigure5 showed general idea of skyline simulation

set on position of GPS digital camera image. Theprogram. DSM (15 meters grid) from satellite Terrasize of cylindrical projection plane was calculated

ASTER VNIR was used in this study. The skyline

from focal length, CCD size of GPS digital camera.

simulation vector data can be generated from DSM.

Figure6 showed generated simulation skyline vector

360 degrees panoramic image should be generated.

data from DSM.

The panoramic image was generated based onFigure5: General Idea of Skyline Simulation Program

Figure6: Generated Simulation Skyline Vector Data with DSM

4.3 Extraction of Skyline from GPS DigitalCamera
The skyline can be also extracted from GPS digital
camera image. The skyline in the image was locatedwhere difference of pixel value was very wide invertical direction. Figure7 showed sample of taken
image with GPS digital camera. Figure8 showed
extracted skyline from GPS digital camera image.

Figure7: GPS Digital Camera Image4.4 Skyline Matching
Figure9 showed outline of skyline matching. First,
the skyline vector data extracted from GPS digital
camera image was compared with the 360 degrees
skyline vector data made from simulation image.
After that, the least of total error is searched formatching. Total error can be calculated by distance
Figure8: Extracted Skyline from GPS Digital

between each skyline vector data.

Figure9: Outline of Skyline Matching

4.5 Calculating Ground Coordinates of Slopedata is generated in ground coordinates.

Failure Area
Figure10 showed shape of disaster on GPS digital
camera image. Figure11 showed general idea ofcalculating ground coordinates of slope failure area.
First, direction of GPS digital camera image iscalculated by skyline matching. Next, the vectors toslope failure area on image is calculated fromcamera direction. After that, ground coordinates ofslope failure area can be extracted from intersection
point of DSM and the vectors to slope failure area on

Figure10: Shape of Disaster on GPS Digital

the image. Finally, shape of slope failure area as GIS

Camera Image

Figure11: General Idea of Calculating Ground Coordinates of Slope Failure Area

Figure12 showed result of extracted disaster on GIS

compass. Table2 showed results of skyline matching.

software.

Number of correct areas were showed 13 areas. The
correct answer means less than 10 degrees
difference.
Table2: Results of succeeded skyline
matchingPoint

Figure12: Shape of Disaster GIS Data on GIS
Software

5. VALIDATION BY FIELD SURVEY
Field surveying with GPS digital camera wascarried out for verification of this system. In 29
points, GPS digital camera images had taken.

A
BC
DE
FGH
I
JKL
M
NO
P
Q
RS
TU
VW
X
YZAAABAC

Surveyed Disaster Area
Azimuth from North

Calculated Disaster Area Difference of Surveyed Azimuth
Azimuth from North

300
330
2078
3178
91
177
44
69
112
315
350
80
345
285
23
85
175
268
322
350
40
85
125
115
35
325
280

291.47326.93
23.55
63.63
55.26
75.05
91.26
172.00
28.56
62.71
82.82
75.93
344.98316.80290.17274.01
293.62304.61306.61
256.53319.02343.7548.79
85.50
112.11143.9932.69
264.65324.91and Calculated Azimuth

8.53
3.07
3.55
14.37
24.26
2.95
0.26
5.00
15.44
6.29
29.18
239.07
5.02
236.8054.83
10.99
270.62219.61131.61
11.47
2.98
6.25
8.79
0.50
12.89
28.99
2.31
60.35
44.91

Accuracy of skyline matching is verified by

Figure13 showed GPS camera image in correctcomparing vector azimuth of view point to center ofmatching point (Point G). The skyline in this image

generated GIS data and measured azimuth withhad very characteristic shape.

condition.
This system takes time for about 30 minutes tocalculate. In future, this problem must be also
solved.

REFERENCES
H. Kobayashi and T. Sanga, Landslide vulnerability
Figure13: GPS camera image in correct

mapping using GIS and spatial statistical analysis,

matching point (Point G)

Journal of the Japan Landslide Society, Japan, pp.

Figure14 showed GPS camera image in failure

1-12, 2005

matching point (Point L). The skyline of this image
had very simple shape. Probably, skyline matching isN. Sawano and others, Disaster Information Exchan-easy to fail in case of shape of the skyline is simple.

ge System by Using “Denshi Kokudo” Web System,
The International Symposium on Management
Systems for Disaster Prevention, Japan, 2006

S. Goto, D. Miyata, Hai-Sheng Fan and T. Sakai,Risk Communication for Oil Spill Accident Using
GIS, The International Symposium on Management
Systems for Disaster Prevention, Japan, 2006
Figure14: GPS camera image in failure
matching point (Point L)

Jong-Hyeok Jeong, K. Kinoshita, Y. Yamamoto, M.

These problems may be influenced by accuracy ofMuneishi and M. Takagi, A Practical Method for

DSM and actual skyline will be changed by weather

Disaster Monitoring, The International Symposium

condition.

on Management Systems for Disaster Prevention,
Japan, 2006

6. CONCLUSIONSThe system of converting slope disaster area in

the University of Minnesota, URL:

image to GIS data with skyline matching was

http://mapserver.gis.umn.edu/, Mapserver

developed. However, the accuracy of skyline
matching is not so good. A reason of miss matching

RICOH CO. LTD, 2000, Specification of RDC-i700,

might be come from accuracy of DSM and weather

RDC-i700 manual

condition.
Correct ratio may be raised by using high resolution

I-O DATA DEVICE. INC, 2002, Specification ofDSM. The panoramic image should be generated by

CFGPS2, CFGPS2 manual

considering visibility of image for using by weather