# pyart.core.geographic_to_cartesian_aeqd¶

pyart.core.geographic_to_cartesian_aeqd(lon, lat, lon_0, lat_0, R=6370997.0)[source]

Azimuthal equidistant geographic to Cartesian coordinate transform.

Transform a set of geographic coordinates (lat, lon) to Cartesian/Cartographic coordinates (x, y) using a azimuthal equidistant map projection 1.

\begin{align}\begin{aligned}x = R * k * \cos(lat) * \sin(lon - lon_0)\\y = R * k * [\cos(lat_0) * \sin(lat) - \sin(lat_0) * \cos(lat) * \cos(lon - lon_0)]\\k = c / \sin(c)\\c = \arccos(\sin(lat_0) * \sin(lat) + \cos(lat_0) * \cos(lat) * \cos(lon - lon_0))\end{aligned}\end{align}

Where x, y are the Cartesian position from the center of projection; lat, lon the corresponding latitude and longitude; lat_0, lon_0 are the latitude and longitude of the center of the projection; R is the radius of the earth (defaults to ~6371 km).

Parameters
• lon, lat (array-like) – Longitude and latitude coordinates in degrees.

• lon_0, lat_0 (float) – Longitude and latitude, in degrees, of the center of the projection.

• R (float, optional) – Earth radius in the same units as x and y. The default value is in units of meters.

Returns

x, y (array) – Cartesian coordinates in the same units as R, typically meters.

References

1

Snyder, J. P. Map Projections–A Working Manual. U. S. Geological Survey Professional Paper 1395, 1987, pp. 191-202.