healpy_healpix_map_creation_smoothing_mollweide_visualization.py

1import numpy as np
2import healpy as hp
3import matplotlib.pyplot as plt
4
5# Set the resolution (nside must be a power of 2)
6nside = 32
7npix = hp.nside2npix(nside)
8
9# Create a sample map: a simple gradient based on pixel indices
10m = np.arange(npix, dtype=float)
11
12# Smooth the map with a Gaussian beam (FWHM in radians)
13# This involves a Spherical Harmonic Transform (map -> alm -> map)
14m_smoothed = hp.smoothing(m, fwhm=np.radians(5.0))
15
16# Visualize the map using a Mollweide projection
17hp.mollview(m_smoothed, title="Healpy Quickstart: Smoothed Map")
18hp.graticule()
19
20# Display the plot
21plt.show()