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Method of Demarcation for Grid Square
The main Grid Square Statistics compiled by the government institutions including the Statistics Bureau of the Ministry of Internal Affairs and Communications are based on Announcement No.143, using the Standard Grid Square.
In this announcement, the Standard Grid Square is divided into three categories: Basic Grid Square, Divided Grid Square and Integrated Grid Square, describing the method of demarcation for each Grid Square and the definition of each code.
The method of demarcation for the Standard Grid Square is as follows:
A Primary Area Partition is demarcated by 40 minutes of latitude and 1 degree of longitude. The Secondary Area Partition is demarcated by dividing a Primary Area Partition into 64 (8 by 8) equal parts vertically and horizontally, and the Basic Grid Square (Third Area Partition) is demarcated by dividing a Secondary Area Partition into 100 (10 by 10) equal parts vertically and horizontally.
| Partition | Method of demarcation | Interval of latitude | Interval of longitude | Length of side | Relation with map |
|---|---|---|---|---|---|
| Primary Area Partition | Divide the country into some equal parts measuring 2/3 degree of latitude by 1 degree of longitude. | 40 minutes | 1 degree | about 80 km | One page of 1/200,000 Regional Map (published by the Geospatial Information Authority of Japan) |
| Secondary Area Partition (Integrated Grid Square) |
Divide a Primary Area Partition into 64 (8 by 8) equal parts towards longitude and latitude. | 5 minutes | 7 minutes 30 seconds | about 10 km | One page of 1/25,000 Topographic Maps (published by the Geospatial Information Authority of Japan) |
| Basic Grid Square (Third Area Partition) | Divide a Secondary Area Partition into 100 (10 by 10) equal parts towards longitude and latitude. | 30 seconds | 45 seconds | about 1 km | |
| Half Grid Square (Divided Grid Square) |
Divide a Basic Grid Square (Third Area Partition) into 4 (2 by 2) equal parts towards longitude and latitude. | 15 seconds | 22.5 seconds | about 500 m | |
| Quarter Grid Square (Divided Grid Square) |
Divide a Basic Grid Square (Third Area Partition) into 16 (4 by 4) equal parts towards longitude and latitude. | 7.5 seconds | 11.25 seconds | about 250 m |
