Databases Reference
In-Depth Information
when the Geographical Survey Institute (GSI), Ministry of Construction (MOC)
began to publish digital cartographic data sets in 1993. Phase III started in 1995
when the government reached a consensus that the active encouragement of GIS
development was necessary. At present, Phase IV is progressing when the
preparation of spatial database in accordance with a standard is important. Below,
phases I and II are explained. Phase III is explained in section 2.2.
2.1.2
Development of Digital National Land Information
The Japanese government has been developing digital geographic information since
the mid-1970s. As its initial activity, GSI began to develop the “Digital National
Land Information” in 1974 in cooperation with the National Land Agency (NLA),
and was nearly completed in 1980. Its accuracy corresponds to approximately
1:200000 paper maps. It consists of DEM, land-use data, boundaries of local
governments, major roads, railways, rivers, coastal lines, public facilities, etc. The
purpose of this project was to supply basic digital geographic data necessary for
national land development planning and regional planning by the central
governmental agencies and local governments.
It has also prepared the “Detailed Digital Land Use Data” to support the policy
making of building land administration in collaboration with the Economic Affairs
Bureau of MOC since 1981. It is a data set of grid cells for land use (10m square
on the ground) for three major metropolitan areas (Tokyo area, Osaka area, and
Nagoya area), and each area is surveyed repeatedly every 5 years.
These data sets have been highly reputed for they have enabled quantitative
analysis of national land. However, they have been specially prepared for
administrative purposes, therefore they have not been disclosed to the public but
used only by administrators within the central and local governments and
researchers at universities.
2.1.3
Publication of Digital Geographic Information
In June 1993, GSI launched into the publication of digital cartographic data sets
called the “Digital Map Series”. It was extremely epoch-making. Since then, the
variation and number of published digital cartographic data and software that
apply those data have increased, and as a result, people have gradually come to
recognize the benefits of geographic information.
Nine kinds of “Digital Map Series” are available at present. They are “Digital
Map 10000 (total),” “Digital Map 25000 (shore lines and administrative
boundaries),” “50m mesh (elevation),” “250m mesh (elevation),” “1km mesh
(elevation),” “1km mesh (average elevation),” “Digital Map 25000 (Map Image),”
“Digital Map 2500 (Spatial Data Framework),” and “Digital Map 200000 (shore
lines and administrative boundaries)”. They are text files and distributed via CD-
ROM with simple software for quick browsing of the image of inside data.
