Dimension

class lsst.daf.butler.Dimension(universe, name, config)

Bases: lsst.daf.butler.DimensionElement

A discrete dimension of data used to organize Datasets and associate them with metadata.

Dimension instances represent concepts such as “Instrument”, “Detector”, “Visit” and “SkyMap”, which are usually associated with database tables. A DatasetType is associated with a fixed combination of Dimensions.

Dimension objects are not directly constructable; they can only be obtained from a DimensionGraph.

Attributes Summary

doc	Documentation for this dimension (str).
hasRegion	Whether this dimension is associated with a region on the sky (bool).
link	Primary key fields that are used only by this dimension, not any dependencies (frozenset of str).
name	Name of this dimension (str, read-only).
primaryKey	The names of fields that uniquely identify this dimension in a data ID dict (frozenset of str).
universe	The graph of all dimensions compatible with self (DimensionGraph).

Methods Summary

dependencies([required, optional])	Return the set of dimensions this dimension depends on.
graph([optional])	Return the minimal DimensionGraph that contains self.

Attributes Documentation

doc

Documentation for this dimension (str).

hasRegion

Whether this dimension is associated with a region on the sky (bool).

link

Primary key fields that are used only by this dimension, not any dependencies (frozenset of str).

name

Name of this dimension (str, read-only).

Also assumed to be the name of any associated table or view.

primaryKey

The names of fields that uniquely identify this dimension in a data ID dict (frozenset of str).

universe

The graph of all dimensions compatible with self (DimensionGraph).

Methods Documentation

dependencies(required=True, optional=False)

Return the set of dimensions this dimension depends on.

Parameters:

required : bool

If True (default), include required dependencies. Required dependences are always expanded recursively.

optional : bool

If True, return optional dependencies.

Returns:

dependencies : DimensionSet

graph(optional=False)

Return the minimal DimensionGraph that contains self.

Parameters:

optional : bool

If True, include optional as well as required dependencies.

Returns:

graph : DimensionGraph