healpix_geo.auto.healpix_to_lonlat#

healpix_geo.auto.healpix_to_lonlat(ipix, grid, *, num_threads=0)#

Get the longitudes and latitudes of the center of some HEALPix cells.

Parameters:

  • ipix (numpy.ndarray) – The HEALPix cell indexes given as a np.uint64 numpy array.

  • grid (Grid) – The definition of the HEALPix grid.

  • num_threads (int, optional) – Specifies the number of threads to use for the computation. Default to 0 means it will choose the number of threads based on the RAYON_NUM_THREADS environment variable (if set), or the number of logical CPUs (otherwise)

Returns:

lon, lat (numpy.ndarray) – The coordinates of the center of the HEALPix cells given as a longitude, latitude tuple.

Examples

>>> import healpix_geo.auto as hg
>>> import numpy as np
>>> ipix = np.array([42, 6, 10])
>>> grid = hg.Grid(level=3, indexing_scheme="nested", ellipsoid="WGS84")
>>> lon, lat = hg.healpix_to_lonlat(ipix, grid)
>>> lon
array([ 5.625, 50.625, 28.125])
>>> lat
array([41.93785391, 19.55202227, 19.55202227])