chaosmagpy.chaos.load_IGRF_txtfile¶
- chaosmagpy.chaos.load_IGRF_txtfile(filepath, name=None)[source]¶
Load the IGRF internal field model from the TXT-file with the piecewise-polynomial coefficients.
- Parameters:
- filepathstr
Path to the IGRF TXT-file (not part of ChaosMagPy).
- namestr, optional
User defined name of the model. Defaults to the filename without the file extension.
- Returns:
Notes
The field is linearly extrapolated in the 5-year period at the end of the model time interval (i.e. in the period 2020-2025 for IGRF-13) using the predictive secular variation in the IGRF.
References
The latest IGRF coefficients can be downloaded at https://www.ncei.noaa.gov/products/international-geomagnetic-reference-field.
Examples
import chaosmagpy as cp import matplotlib.pyplot as plt import numpy as np model = cp.load_IGRF_txtfile('irgf13coeffs.txt') # load model TXT-file fig, ax = plt.subplots(1, 1, figsize=(10, 6)) time = np.linspace(1900., 2020., 1000) # decimal years mjd = cp.data_utils.dyear_to_mjd(time, leap_year=True) coeffs = model.synth_coeffs(mjd, nmax=1) ax.plot(time, coeffs) ax.set_title(model.name) ax.set_xlabel('years') ax.set_ylabel('nT') ax.legend(['$g_1^0$', '$g_1^1$', '$h_1^1$']) plt.tight_layout() plt.show()