SkyPixSystem

class lsst.daf.butler.SkyPixSystem(name: str, *, maxLevel: int, PixelizationClass: type[lsst.sphgeom.pixelization_abc.PixelizationABC])

Bases: TopologicalFamily

Class for hierarchical pixelization of the sky.

A TopologicalFamily that represents a hierarchical pixelization of the sky.

Parameters:

namestr

Name of the system.

maxLevelint

Maximum level (inclusive) of the hierarchy.

PixelizationClasstype (lsst.sphgeom.PixelizationABC subclass)

Class whose instances represent a particular level of this pixelization.

Methods Summary

choose(dimensions)	Select the best member of this family to use.
make_column_reference(endpoint)	Create a column reference to the generalized region column for the given endpoint.

Methods Documentation

choose(dimensions: DimensionGroup) → SkyPixDimension

Select the best member of this family to use.

These are to be used in a query join or data ID when more than one is present.

Usually this should correspond to the most fine-grained region.

Parameters:

dimensionsDimensionGroup

Dimensions to choose from, if this is a dimension-based topological family.

Returns:

bestTopologicalRelationshipEndpoint

The best endpoint from this family for these dimensions.

make_column_reference(endpoint: TopologicalRelationshipEndpoint) → DimensionFieldReference

Create a column reference to the generalized region column for the given endpoint.

Parameters:

endpointTopologicalRelationshipEndpoint

Endpoint to create a column reference to.

Returns:

columnqueries.tree.ColumnReference

Column reference.