Databases Reference
In-Depth Information
papers, which were hard to handle directly on computers. With the evolution of
digital geographical data, we are now at a high stage of using these data
interoperably via networks throughout the world in a variety of fields. Here,
standardization of GIS data plays a crucial role, and in fact several important
standardization activities have been performed. In the first half of this paper, we
survey GIS developments in Japan for maintaining geographical data and for
contributions in standardization work. Some of activities of a representative
governmental institute performing research and servicing on geographical data
are described, together with some of typical digital geographical data maintained
so far in Japan.
One of the most frequently used GIS systems in Japan would be the car navigation
system. For example, dynamical traffic information newly becomes available such
as ATIS (Advanced Traffic Information Service) and VICS (Vehicle Information &
Communication System) besides compact car navigation systems attached to
vehicles, based on the GIS infrastructure. In the latter half of this paper, we describe
some of research results on GIS from the standpoint of spatial data mining,
computational geometry, and network algorithms. These include demonstration
of a
k
-means algorithm for spatial data mining, the problem of inferring topological
information from digital map, and the label placement problem for node and edge
features in maps. Also, as an interesting issue in ITS (Intelligent Transport System),
the problem of finding useful detours in car navigation is discussed.
By covering the two aspects of GIS in the above-mentioned way, this paper tries
to give outline of some of GIS infrastructure and GIS research in Japan.
2
GIS Developments in Japan
In this section, recent GIS-related activities in Japan are described. The section
covers three subjects. The first subject is digital map preparation, which was initiated
about 25 years ago. At that time, there was no such concept as spatial database,
and efficient map digitization was a main research problem. The second subject
topic is recent GIS-related activities by the Japanese government. Information on
current activities and the policy of Japanese government are presented. The third
topic is about the Spatial Data Framework, which was developed under the new
concept of spatial database.
2.1
Development and Publication of Map Data
2.1.1
Outline
The development process of GIS infrastructure in Japan can be explained in four
phases. Phase I began in the middle of the 1970s when the government started
preparation of digital geographic data for only limited users such as central and
local governmental organizations and researchers at universities. Phase II arrived
