NE RPC NT
4.6. Metadata
Metadata, which explain about the contents, quality, contition and
other characteristics of the data, are prescribed as the metadata
components which are discussed under the 211“ Technical
Committee of the International Standard Organization (ISO/TC211).
The draft which has been submitted at the committee classifies nine
categories of metadata and prescribes each category in detail.
Followings are the outline of each category.
e Identification information: Basic information about the
data set.
e - Data Quality Information: General assessment of the
quality of the data set.
® Spatial Data Organization Information. Mechanism used
to represent spatial information in the data set.
® Spatial Reference Information: The description of the
reference frame for, and the means to encode, coordinates in
the data set.
e Entity and Attribute Information: Information about the
information content of the data set, including the entities’
types, their attributes and the domains from which attribute
values may be assigned.
e Distribution Information: Information about the
distribution of and options for obtaining the data set.
e Metadata Reference Information: Information on the
currentness of the metadata information and the responsible
party.
© Citation Information: Recommended reference to be
used for the data set.
® Contact Information: Identity of, and means to
communicate with, person(s) and organization(s) associated.
In ISO/TC211, they also have offered a detail metadata sample
referring to above categories. They are divided into three levels
according to the requirement, mandate, conditional and optional. In
the Global Map technical specifications, mandate metadata items
and the metadata items appropriate for Global Map are prescribed as
mandate items.
5. Prototype Version of Global Map Data
Japan
In order to contribute to the discussion of technical specifications and
verification of the specifications, Geographical Survey Institute
made Global Mapping Data Japan Edition 0 which covered the
whole land area of Japan. These data were provided at the Global
Mapping Forum '97 in Gifu and have been opened to the public
widely. Since February 1998, they have been accessible through the:
Internet with the following URL.
http://www] .gsi-mc.go.jp/ch3www/globalmap-
gsi/gmdata-japan.html
More than 1000 accesses are recorded every month (as of March
1998).
i Evergreen broad-leaved forest
| Deciduous broad-leaved forest
Grassland in temperate zone
|Semi-desert in temperate zone
Desert in temperate zone
Northern coniferous forest
Figure 4 of the vegetation layer the
This data set is generated from the existing digital geographic data
possessed by Geographical Survey Institute. The geodetic coordinate
system of these original data was different from the one adopted in
the specifications. Therefore, all of the coordinate in the data set
were converted to the ITRF94 system in advance. In the vector form
data, the attributes in Japanese are written by Roman characters.
In processing the geographic data in vector form, position and shape
of each feature, and its attribute are extracted from the original data
set separately. They are integrated into one data set after the
necessary processing mentioned above. Then generalization are
applied to the data set and metadata are attached. The outline of the
entire processing is illustrated as follows (Figure 5).
In processing raster form data, final products are resampled from
original data by the nearest neighborhood method.
488 International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
