Handling of the relationship between magnetic north and true north

　According to the measurement results of 2000 by the Geographical Survey Institute of the Ministry of Land, Infrastructure, Transport and Tourism, the difference between the magnetic north and true north (magnetic polarization) of the most city area was 7 degrees, and the magnetic polarization angle in the city is 7 degrees. I will treat it as
　Regardless of the above magnetic angle, it is acceptable to determine the true north direction based on the actual measurement of the solar position and the basic map of city planning (topographic map) etc.
　The effective date of application is December 1, 2007.
※When calculating the orientation angle by on-site measurement, it is necessary to pay attention to consistency with the basic map of city planning <topographic map>.