hipscatalog_gen.healpix.densmap.densmap_for_depth_delayed

densmap_for_depth_delayed(ddf, ra_col, dec_col, depth)[source]

Build a delayed HEALPix density map at a given depth.

For HATS/LSDB catalogs with a HEALPix nested index named “_healpix_<order>”, the density map is derived by bit-shifting that index to the requested depth. For other inputs, pixel indices are computed from RA/DEC.

Parameters:

  • ddf (Any) – Dask-like collection or LSDB catalog.

  • ra_col (str) – RA column name (degrees).

  • dec_col (str) – DEC column name (degrees).

  • depth (int) – HEALPix order (depth).

Returns:

Dask delayed object that evaluates to a 1D numpy array of counts.