Failu krātuve :: GeoMag/
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about.txt 2017-11-04 07:46 3.2K Text, ASCII format
adrese.txt 2017-11-04 08:01 317 Addresses, URL
EMM2015_Sph_Linux.zip 2017-11-04 07:47 14M Compressed archive
EMM2015_Sph_Mac.zip 2017-11-04 07:47 14M Compressed archive
EMM2015_Sph_Windows.zip 2017-11-04 07:47 14M Compressed archive
EMM2017_Sph_Linux.zip 2017-11-04 07:47 13M Compressed archive
EMM2017_Sph_Windows.zip 2017-11-04 07:47 15M Compressed archive
geomag70_linux.tar.gz 2017-11-04 07:31 153K Compressed archive
geomag70_windows.zip 2017-11-04 07:31 163K Compressed archive
geomagz.exe 2017-11-04 08:19 102K Executable binary
if_internet_earth_61632.ico 2017-11-04 08:06 75K Picture, Icon file
igrf12.f 2017-11-04 07:31 56K
igrf12coeffs.txt 2017-11-04 07:29 38K Text, ASCII format
IGRF12coeffs.xls 2017-11-04 07:30 66K SpreadSheet
WMM2015_Linux.tar.gz 2017-11-04 07:41 12M Compressed archive
WMM2015_Report.pdf 2017-11-04 07:40 17M Digital document (Acrobat)
WMM2015_Windows.zip 2017-11-04 07:41 12M Compressed archive
WMM2015COF.zip 2017-11-04 07:39 1.8K Compressed archive
WMM2015GUI.zip 2017-11-04 07:42 4.5M Compressed archive
WMM2015LegacyC.zip 2017-11-04 07:44 152K Compressed archive
WMM2015LegacyFortran.zip 2017-11-04 07:43 912K Compressed archive
WMM2015testvalues.pdf 2017-11-04 07:43 46K Digital document (Acrobat)
WMMMaps2015.zip 2017-11-04 07:40 51M Compressed archive
The study of geomagnetism is one of the oldest of the geophysical sciences. The geomagnetic fields
have been observed and used from ancient times. Modern uses of geomagnetic data include navigation
and mineral exploration. The National Centers for Environmental Information develops and distributes
models of the geomagnetic field and maintains archives of geomagnetic data to further the understanding
of Earth magnetism and the Sun-Earth environment.
Geomag 7.0 Software: license and copyright information
The geomag 7.0 software code is in the public domain and not licensed or under copyright. The information
and software may be used freely by the public. As required by 17 U.S.C. 403, third parties producing
copyrighted works consisting predominantly of the material produced by U.S. government agencies must provide
notice with such work(s) identifying the U.S. Government material incorporated and stating that such material
is not subject to copyright protection.
The World Magnetic Model (WMM2015)
The World Magnetic Model is a joint product of the United States' National Geospatial-Intelligence Agency (NGA)
and the United Kingdom's Defence Geographic Centre (DGC). The WMM was developed jointly by the National
Geophysical Data Center (NGDC, Boulder CO, USA) (now the National Centers for Environmental Information (NCEI))
and the British Geological Survey (BGS, Edinburgh, Scotland).
The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence,
the North Atlantic Treaty Organization (NATO) and the International Hydrographic Organization (IHO), for navigation,
attitude and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation
and heading systems. The model, associated software, and documentation are distributed by NCEI on behalf of NGA.
The model is produced at 5-year intervals, with the current model expiring on December 31, 2019.
Enhanced Magnetic Model (EMM)
The Earth's internal magnetic field is a superposition of the field generated by the geodynamo in the liquid outer
core (main field) and the field of magnetized rocks in the crust and upper mantle. The main field dominates the long
wavelengths, whereas the crustal field dominates at wavelengths smaller than 2500 km.
Geomagnetic field models are conveniently represented as spherical harmonic expansions of a scalar magnetic potential.
Such a model can then be evaluated at any desired location to provide the magnetic field vector, its direction, and
strength. The standard World Magnetic Model uses a spherical harmonic representation to degree and order 12, resolving
the magnetic field at 3000 km wavelength. In contrast, the Enhanced Magnetic Model (EMM) extends to degree and order
790, resolving magnetic anomalies down to 51 km wavelength (see comparison in the figure). The higher resolution of
the EMM results in significantly improved pointing accuracy.
The EMM model was compiled from satellite, marine, aeromagnetic and ground magnetic surveys. The EMM2017 includes data from the European Space Agency's Swarm satellite mission. This constellation of satellites currently represents the best source of data about the evolution of the Earth's main magnetic field.
Lapas adrese: priede.bf.lu.lv/ftp/pub/TIS/datu_analiize/GeoMag