AACGMv2

A Python wrapper for the AACGM-v2 C library that converts between geographic and Altitude Adjusted Corrected Geomagnetic (AACGM) coordinates and between AACGM longitude and magnetic local time.

AACGMv2 is a Python wrapper for the AACGM-v2 C library, which converts between geographic (geodetic or geocentric) coordinates and Altitude Adjusted Corrected Geomagnetic (AACGM) coordinates, and between AACGM longitude and magnetic local time (MLT). AACGM coordinates are a magnetic-field-based coordinate system in which points along the same geomagnetic field line share a common latitude and longitude, which makes them well suited to high-latitude ionospheric studies and to magnetosphere-ionosphere coupling and conjugate work. The package returns magnetic latitude, magnetic longitude and MLT for single values or for arrays, computing them either from precomputed spherical harmonic coefficients or by tracing IGRF field lines, with the ALLOWTRACE, TRACE and BADIDEA method codes controlling that choice. It also provides utilities for geocentric-to-geodetic latitude conversion, the subsolar point, and the IGRF dipole axis. The bundled C library is version 2.7 and ships AACGM-v2 coefficients derived from IGRF-14 together with a combined GUFM1/IGRF magnetic field model spanning 1590-2025. Coefficient-based conversions are valid up to 2000 km altitude, and AACGM coordinates are undefined near the magnetic equator, where the routines return NaN. Both a Python API and a command-line interface that reads and writes whitespace-delimited ASCII files are provided. When referencing this package, cite both the package DOI and the AACGM-v2 journal article, Shepherd (2014), doi:10.1002/2014JA020264.