# AACGM-v2 Coordinate Transformations

A calculator for transformations between geographic and AACGM-v2
coordinates. For details of the underlying technique, please see
preprint [Shepherd, S. G. (2014),
Altitude-adjusted corrected geomagnetic coordinates: Definition and functional
approximations, *J. Geophys. Res., 119, 9, * doi:10.1002/2014JA020264.]
Supported, in part, by NSF Award ATM-0838356.

## AACGM-v2 Calculator

**Important Notes:**

**1.**The coefficients and software used for these calculations are

**different from the historical AACGM coefficients**.

The transformations used here will almost certainly result in different numbers than would be obtained from the historical AACGM software, but

they are

**more accurate**. Please see the following preprint for details.

**2.**Multiple values for date, latitude, longitude and altitude are allowed:

- Numbers must be separated by commas

- Lists of numbers must either be the same length or a scalar

**3.***Altitudes above 2000 km require the field-line tracing button to be selected.

**4.****For

**G2A**input altitude(s) are either geodetic (height above sea level) or geocentric (height above sphere RE = 6372.1 km).

Output altitude(s) are geocentric height for both geodetic and geocentric inputs. For

**A2G**input altitude(s) are

geocentric. Output altitudes(s) are either geodetic or geocentric depending on the output selected.

**5.**Geographic coordinates can be specified as either geodetic or geocentric. If geodetic is selected then coordinates are transformed to geocentric before

converting to AACGM. For inverse transformations (AACGM to geographic) the resulting geographic coordinates are transformed to geodetic coordinates.