磁偏角 如何查?──世界磁偏角數據變化的官方網站

何有

http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

http://www.ngdc.noaa.gov/geomag-web/#declination

Search NGDC Search NOAA

NOAA > NESDIS > NGDC > Geomagnetism	comments | privacy policy

Estimated Value of Magnetic Declination To compute the magnetic declination, you must enter the location and date of interest. If you are unsure about your city's latitude and longitude, look it up online! In the USA try entering your zip code in the box below or visit the U.S. Gazetteer. Outside the USA try the Getty Thesaurus. Search for a place in the USA by Zip Code:

Enter Location: (latitude 90S to 90N, longitude 180W to 180E). See Instructions for details. Latitude: N S Longitude: E W Enter Date (1900-2010): Year: Month (1-12): Day (1-31):

何有

查全球磁偏角歷史：

Magnetic declination

http://www.ngdc.noaa.gov/geomagmodels/USHistoric.jsp

NOAA > NESDIS > NGDC > Geomagnetism	comments | privacy policy

This programs derives a table of secular change in magnetic declination for a specified point in the conterminous United States. It utilizes the USD polynomial & the IGRF spherical harmonic models. Declination is shown to the nearest minute so that secular change may be properly illustrated, but it is usually only accurate to within 30 minutes.

Location		Degree	Minute		Date
Zip Code:	Northern Latitude:			Start Date:
	Western Longitude:			End Date:

＝────────────────────────────────────────────────────────────────────────

http://www.resurgentsoftware.com/gpetrie/GeoMag/geomag25.exe

天機

最新的 NOAA 磁偏角官方計算工具: http://www.ngdc.noaa.gov/geomag-web/#igrfwmm

小老头

宋人不会计算，也不知道磁偏角的存在吧