Astronomical datasets have various dimensions, for example, 1D spectra or table columns, 2D images, or 3D Integral field data cubes.
Datasets can also have various numeric data types, depending on the operation/purpose, for example, processed images are commonly stored in floating point format, but their mask images are integers (allowing bit-wise flags to identify certain classes of pixels to keep or mask, see Numeric data types).
Certain other information about a dataset are also commonly necessary, for example, the units of the dataset, the name of the dataset and some comments.
To deal with any generic dataset, Gnuastro defines the
gal_data_t as input or output.