scope:

These specifications are designed to provide guidelines for the preparation and use of the spherical harmonic World Magnetic Model (WMM) and the charts and grid tables derived from the model. These specifications also provide guidelines for the preparation and use of computer programs and subroutines, distributed under the name GEOMAG, that compute from the model magnetic field parameters such as declination (D), inclination (I), total intensity (F), horizontal intensity (H), vertical component (Z), and grid variation (G) at any desired point below, on, or above the Earth's surface at any time during the 5-year lifetime of the model.

The purpose of this document is to specify the WMM and the Defense Mapping Agency (DMA) products that are derived from the model. This document also specifies the accuracy and limitations of the model.

This military specification is UNCLASSIFIED.

The WMM spherical harmonic coefficients, related computer software, charts, grids and other products derived from the model are UNCLASSIFIED. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Director, Defense Mapping Agency, ATTN: PR, ST A-13, 8613 Lee Highway, Fairfax, VA 22031-2137 by using the Standardization Document Improvement Proposal (DD Form 11426) appearing at the end of this document or by letter.

intended Use: