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77?e International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
Absolute accuracy is defined as the difference 
between the stored coordinates and the true 
coordinates for a specific point. 
For horizontal accuracy, 90% of points will be within 
±2km of their actual location. In the case of data 
obtained from satellite images, the maximum error is 
less than or equal to 0.5km.July, 2007. Vertical 
accuracy is notionally ±150 meters for 90% of points. 
This figure may need to be reviewed once the data are 
available, as sources to this accuracy may not be 
available in areas of high relief. 
The format for vector data are the Vector Product 
Format (VPF), which are developed United States 
National Imagery and mapping Agency (NIMA). For 
raster data, the format is Band Interleaved by Line 
(BIL) with separate headers. 
5. Data Development 
Participants are expected to develop Global Map data 
of their own countries. But for some countries, it isn’t 
easy to develop the data by themselves because of 
their financial or technical situations. For those 
countries, other some countries, such as Japan, 
support them to develop their data. In general, the 
Global Map data are developed from existing small 
scale maps of the country or region. But existing 
global digital data set such as V-map 0 or satellite 
images are used in case of there are no appropriate 
data for Global Map (Figure 3.). 
Existing Information 
Figure 3. Data Development 
Global Map 
Data which are developed as source of the Global 
Map will be sent to the Secretariat and converted to 
the Global Map format. Finally, converted data will be 
sent back to the concerned country and are checked 
again by them. The process of data development and 
the role of ISCGM are shown in figure 4. 
Development 
Release 
Application 
Figure 4 Framework of the project 
Land cover, land use and vegetation layers, they were 
similar concepts and it is difficult for some countries 
to develop these layers by themselves. Therefore, 
ISCGM studied this issue and concluded that it was 
effective to develop land cover and vegetation layers 
not for country by country but for whole globe using 
satellite images. Based on this new idea, these two 
layers are developed and released in June, 2008. Main 
works have done by GSI and Chiba university of 
Japan but other NMOs also played important role such 
as collection of GCP and validation works for 
improving quality of the data. Specification has been 
also revised for these two layers. New vegetation layer 
is percent tree cover by 1km mesh. Land surfaces are 
classified into 20 land covers in new layer. 
6. Data release 
The developed data as the Global Map are released 
separately by country or region. In year of 2000, the 
data of Japan, Nepal, Laos, Sri Lanka and Thailand 
have been released for the first time. But the number 
of countries and regions which released their Global 
Map has not increased so fast in those days. Therefore, 
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