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# -*- coding: utf-8 -*- |
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# vim:fileencoding=utf-8 |
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# |
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# Copyright (c) 2018 Stefan Bender |
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# |
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# This file is part of sciapy. |
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# sciapy is free software: you can redistribute it or modify it |
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# under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, version 2. |
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# See accompanying LICENSE file or http://www.gnu.org/licenses/gpl-2.0.html. |
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"""AACGM 2005 geomagnetic model at 80 km |
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""" |
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from __future__ import absolute_import, division, print_function |
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import logging |
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from pkg_resources import resource_filename |
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import numpy as np |
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from scipy.interpolate import RectBivariateSpline |
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import xarray as xr |
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__all__ = ['gmag_aacgm2005'] |
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def gmag_aacgm2005(lat, lon, aacgm_name="AACGM2005_80km_grid.nc"): |
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"""Fixed 2005 AACGM geomagnetic coordinates at 80 km |
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Geomagnetic coordinates according to the AACGM model but |
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with fixed parameters for the 2005 epoch. |
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Parameters |
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---------- |
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lat: array_like |
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Geographic latitude(s) in degrees north |
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lon: array_like |
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Geographic longitude(s) in degrees east |
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aacgm_name: str, optional |
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Filename of the AACGM grid, relating geographic latitude |
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and longitude to AACGM geomagnetic latitude and longitude. |
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The default is the prepared grid file for 2005 and at 80 km. |
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Returns |
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------- |
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aacgmlat: numpy.ndarray or float |
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The AACGM 2005 geomagnetic latitude(s) |
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aacgmlon: numpy.ndarray or float |
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The AACGM 2005 geomagnetic longitude(s) |
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""" |
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aacgm_file = resource_filename(__name__, aacgm_name) |
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logging.debug("aacgm_file: %s", aacgm_file) |
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# Fix longitudes to +- 180 |
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lon = (np.asarray(lon) + 180.) % 360. - 180. |
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aacgm_ds = xr.open_dataset(aacgm_file) |
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lats = aacgm_ds["Latitude"] |
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lons = aacgm_ds["Longitude"] |
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glats = aacgm_ds["Geomagnetic_latitude"] |
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glons = aacgm_ds["Geomagnetic_longitude"] |
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splglat = RectBivariateSpline(lats, lons, glats) |
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splglon = RectBivariateSpline(lats, lons, glons) |
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return (splglat.ev(lat, lon), splglon.ev(lat, lon)) |
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st-bender /
sciapy
