MakeCatalog’s output measurements can be classified into two types: columns (independent measurements on each label) or metadata (of the whole image, see Metameasurements on full input). The precise measurements that it will actually do is specified using command-line options that are described in the subsections below (Options).
The majority of the first group are those which only produce a single-valued measurement for each label (for example, its magnitude: a single number for every label/object). There are also multi-valued measurements per label (like spectra on 3D cubes) which keep their values in a single vector column of the same table (see Vector columns). Both types of measurements will be written as one column in a final table/catalog that also contains all the other requested columns/measurements. Measurements that produce one value for the whole input (not a specific label/object) are stored as metadata in the 0-th (first) HDU of the output with predefined keywords described in Metameasurements on full input.
The majority of this section is devoted to MakeCatalog’s single-valued measurements. However, MakeCatalog can also do measurements that produce more than one value for each label. Currently the only such measurement is generation of spectra from 3D cubes with the --spectrum option and it is discussed in the end of this section.
Command-line options are used to identify which measurements you want in the final catalog(s) and in what order. If any of the options below is called on the command-line or in any of the configuration files, it will be included as a column in the output catalog. The order of the columns is in the same order as the options were seen by MakeCatalog (see Configuration file precedence). Some of the columns apply to both “objects” and “clumps” and some are particular to only one of them (for the definition of “objects” and “clumps”, see Segment). Columns/options that are unique to one catalog (only objects, or only clumps), are explicitly marked with [Objects] or [Clumps] to specify the catalog they will be placed in.
GNU Astronomy Utilities 0.24 manual, November 2025.