EquatSkyMap¶

class lsst.skymap.EquatSkyMap(config=None)¶

Bases: lsst.skymap.BaseSkyMap

Equatorial sky map pixelization, e.g. for SDSS stripe 82 image data.

EquatSkyMap represents an equatorial band of sky divided along declination into overlapping tracts.

Parameters

configlsst.skymap.BaseSkyMapConfig (optional): The configuration for this SkyMap; if None use the default config.

Attributes Summary

`SKYMAP_DATASET_TYPE_NAME`
`SKYMAP_RUN_COLLECTION_NAME`

Methods Summary

`findClosestTractPatchList`(coordList)	Find closest tract and patches that overlap coordinates.
`findTract`(coord)	Find the tract whose center is nearest the specified coord.
`findTractPatchList`(coordList)	Find tracts and patches that overlap a region.
`getSha1`()	Return a SHA1 hash that uniquely identifies this SkyMap instance.
`getVersion`()	Return version (e.g.
`logSkyMapInfo`(log)	Write information about a sky map to supplied log
`register`(name, butler)	Add skymap, tract, and patch Dimension entries to the given Gen3 Butler.
`updateSha1`(sha1)	Add subclass-specific state or configuration options to the SHA1.

Attributes Documentation

SKYMAP_DATASET_TYPE_NAME = 'skyMap'¶

SKYMAP_RUN_COLLECTION_NAME = 'skymaps'¶

Methods Documentation

findClosestTractPatchList(coordList)¶

Find closest tract and patches that overlap coordinates.

Parameters

coordListlsst.geom.SpherePoint: List of ICRS sky coordinates to search for.

Returns

retListlist: list of (TractInfo, list of PatchInfo) for tracts and patches that contain, or may contain, the specified region. The list will be empty if there is no overlap.

findTract(coord)¶

Find the tract whose center is nearest the specified coord.

Parameters

coordlsst.geom.SpherePoint: ICRS sky coordinate to search for.

Returns

resultTractInfo: TractInfo of tract whose center is nearest the specified coord.

Notes

If coord is equidistant between multiple sky tract centers then one is arbitrarily chosen.
The default implementation is not very efficient; subclasses may wish to override.

Warning: If tracts do not cover the whole sky then the returned tract may not include the coord.

findTractPatchList(coordList)¶

Find tracts and patches that overlap a region.

Parameters

coordListlist of lsst.geom.SpherePoint: List of ICRS sky coordinates to search for.

Returns

reListlist of (TractInfo, list of PatchInfo): For tracts and patches that contain, or may contain, the specified region. The list will be empty if there is no overlap.

Notes

warning:: This uses a naive algorithm that may find some tracts and patches that do not overlap the region (especially if the region is not a rectangle aligned along patch x, y).

getSha1()¶

Return a SHA1 hash that uniquely identifies this SkyMap instance.

Returns

sha1bytes: A 20-byte hash that uniquely identifies this SkyMap instance.

Notes

Subclasses should almost always override updateSha1 instead of this function to add subclass-specific state to the hash.

getVersion()¶

Return version (e.g. for pickle).

Returns

resulttuple of int: Version as a pair of integers.

logSkyMapInfo(log)¶

Write information about a sky map to supplied log

Parameters

loglsst.log.Log: Log object that information about skymap will be written

register(name, butler)¶

Add skymap, tract, and patch Dimension entries to the given Gen3 Butler.

Parameters

namestr: The name of the skymap.
butlerlsst.daf.butler.Butler: The butler to add to.

Raises

lsst.daf.butler.registry.ConflictingDefinitionError: Raised if a different skymap exists with the same name.

Notes

Registering the same skymap multiple times (with the exact same definition) is safe, but inefficient; most of the work of computing the rows to be inserted must be done first in order to check for consistency between the new skymap and any existing one.

Re-registering a skymap with different tract and/or patch definitions but the same summary information may not be detected as a conflict but will never result in updating the skymap; there is intentionally no way to modify a registered skymap (aside from manual administrative operations on the database), as it is hard to guarantee that this can be done without affecting reproducibility.

updateSha1(sha1)¶: Add subclass-specific state or configuration options to the SHA1.

Navigation

EquatSkyMap¶