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no mechanism to use these local data for the 
development of global dataset. There are many 
reliable local data without extended use for 
global dataset. Regarding categorized data, 
different classification systems by countries and 
projects prevent the use of local data. Only 
international authorized organization can 
establish new mechanism to integrate local data 
in various countries and projects. 
ETOPOS was the best available global DEM. 
This has five minute grid which is a coarse 
resolution even for global applications, and the 
accuracy is not sufficient. Then GLOBE 
Committee is producing a new global DEM with 
30 second grid using Digital Terrain Elevation 
Data(DTED) which is global DEM with three 
second grid by Defense Mapping Agency 
(DMA), USA. Since DTED has also some 
regions with poor accuracy, remote sensing 
technique such as interferometry has to be used 
to improve the quality of data. Similarly, for 
other environmental variables, new better 
information source has to be used to improve its 
quality. 
Most existing global datasets are not well 
documented about its accuracy. Without 
accuracy data, any result derived from global 
datasets cannot be evaluated in terms of 
reliability. Data without accuracy data is useless. 
Any newly produced global dataset must have a 
documentation about its accuracy. To do this, 
evaluation method of accuracy has to be 
standardized. 
The problem about metadata is similar to the 
above problem. Most existing global datasets 
has no or not enough metadata. Metadata has to 
be attached to all global datasets. The 
International Standards Organization Technical 
Committee 211 (ISO/TC 211) tries to create 
metadata standards for geographic data as a part 
of theirtasks. The metadata standards for global 
datasets has to be created by a group of datasets 
producers, distributors, and users. 
Different classification system of categorized 
data such as land cover and soil type by different 
857 
countries and projects prevent the integration and 
comparison of their data. Harmonization or 
standardization of classification system is 
indispensable. The United Nations 
Environmental Programme (UNEP) and the 
Food and Agriculture Organization (FAO) have a 
valuable project to harmonize existing land cover 
and land use classification system. 
Map projection is another problem. There is no 
best map projection in all requirements. The 
evaluation method of different map projections 
has to be established and better map projections 
for data storage, data analysis, and data 
presentation has to be selected. 
5. WHAT ACTIONS SHOULD ISPRS 
TAKE? 
There are many organizations and project groups 
who recognize the above mentioned problems 
for better global database. They are global 
database planners mentioned in the section 2: 
IGU;. 1CA,- UNEP. .  UNDP Global 
Mapping(Japan), Farth Map(USA), etc. In 
order to avoid a duplication of efforts, The 
ISPRS needs linkage with other groups by 
having a meeting. The purpose of such a 
meeting would be: 
- Common recognition of problems for better 
global database 
- Survey of on-going studies and projects to 
solve problems 
- Identify cooperative actions with other 
organizations and project groups, and assign 
initiative actions by an individual organization 
What can the ISPRS do as initiative actions? 
The ISPRS can 
- document and publish the present situation of 
the development of global datasets and database. 
This makes users, producers, and planners of 
global datasets understand the situation, and 
helps to develop better global database. 
- take part in standardizing metadata 
- study for selecting several map projections as 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996