multiband_asn

Create multiband associations using either the command line tool multiband_asn or through the Python API using romancal.associations.multiband_asn.MultibandAssociation.

Multiband Associations

This module groups input files by their skycell identifier, creating an association file for each unique skycell. Each association file contains all filters (observations) that were used for that specific skycell, allowing for multiband data products to be generated per skycell. This enables efficient organization and processing of data across multiple filters for the same region of the sky.

To create a multiband association, use the following command:

multiband_asn r00001_*full*_coadd.asdf

where the input files are in the current directory and the wildcard expands to all relevant files. The tool will group files by their skycell identifier and generate association files for each group. To get a complete list of options you can run the command with the -h option:

multiband_asn -h

The input filenames should follow the convention:

rPPPPP_<data_release_id>_<product_type>_<skycell_id>_coadd.asdf

Where:

PPPPP = Program number data_release_id = Data release identifier (e.g., ‘p’ for prompt) product_type = Product type (e.g., ‘full’) skycell_id = Skycell identifier (e.g., ‘270p65x48y69’)

The association files will be JSON files named:

rPPPPP_<data_release_id>_<product_type>_<skycell_id>_asn.json

For example, to generate associations for all skycells in a program:

multiband_asn r00001_*full*_coadd.asdf

You can also use the Python API:

from romancal.associations.multiband_asn import MultibandAssociation
files = ["r00001_p_full_270p65x48y69_coadd.asdf", ...]
multiband = MultibandAssociation(files)
multiband.create_multiband_asn()

The data release ID and product type are extracted from the filenames. Association files are generated for each skycell group.