HiPSCat Directory Scheme

Partitioning Scheme

We use healpix (Hierarchical Equal Area isoLatitude Pixelization) for the spherical pixelation, and adaptively size the partitions based on the number of objects.

In areas of the sky with more objects, we use smaller pixels, so that all the resulting pixels should contain similar counts of objects (within an order of magnitude).

File structure

The catalog reader expects to find files according to the following partitioned structure:

__ /path/to/catalogs/<catalog_name>/
   |__ catalog_info.json
   |__ partition_info.csv
   |__ Norder=1/
   |   |__ Dir=0/
   |       |__ Npix=0.parquet
   |       |__ Npix=1.parquet
   |__ Norder=J/
       |__ Dir=10000/
           |__ Npix=K.parquet
           |__ Npix=M.parquet