lsst.skymap.healpixSkyMap.HealpixSkyMap Class Reference

Inheritance diagram for lsst.skymap.healpixSkyMap.HealpixSkyMap:

Public Member Functions
def	__init__ (self, config, version=0)
def	findTract (self, coord)
def	generateTract (self, index)
def	updateSha1 (self, sha1)
def	__reduce__ (self)
def	__iter__ (self)
def	__len__ (self)
def	__getitem__ (self, index)
def	findTractIdArray (self, ra, dec, degrees=False)
def	findTractPatchList (self, coordList)
def	findClosestTractPatchList (self, coordList)
def	__hash__ (self)
def	__eq__ (self, other)
def	__ne__ (self, other)
def	logSkyMapInfo (self, log)
def	getSha1 (self)
def	register (self, name, butler)

Public Attributes
	config

Static Public Attributes
	ConfigClass = HealpixSkyMapConfig
int	numAngles = 4
string	SKYMAP_RUN_COLLECTION_NAME = "skymaps"
string	SKYMAP_DATASET_TYPE_NAME = "skyMap"

Detailed Description

HEALPix-based sky map pixelization.

We put a Tract at the position of each HEALPixel.


Parameters
----------
config : `lsst.skymap.BaseSkyMapConfig`
    The configuration for this SkyMap.
version : `int` or `tuple` of `int` (optional)
    Software version of this class, to retain compatibility with old
    instances.

Definition at line 86 of file healpixSkyMap.py.

Constructor & Destructor Documentation

__init__()

def lsst.skymap.healpixSkyMap.HealpixSkyMap.__init__	(		self,
			config,
			version = 0
	)

Definition at line 104 of file healpixSkyMap.py.

    def __init__(self, config, version=0):
        self._nside = 1 << config.log2NSide
        numTracts = healpy.nside2npix(self._nside)
        super(HealpixSkyMap, self).__init__(numTracts, config, version)
 

Member Function Documentation

__eq__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__eq__ (   self,   other  )

inherited

Definition at line 252 of file baseSkyMap.py.

    def __eq__(self, other):
        try:
            return self.getSha1() == other.getSha1()
        except AttributeError:
            return NotImplemented
 

__getitem__()

def lsst.skymap.cachingSkyMap.CachingSkyMap.__getitem__ (   self,   index  )

inherited

Get the TractInfo for a particular index.

The tract is returned from a cache, if available, otherwise generated
on the fly.

Reimplemented from lsst.skymap.baseSkyMap.BaseSkyMap.

Definition at line 80 of file cachingSkyMap.py.

    def __getitem__(self, index):
        """Get the TractInfo for a particular index.
 
        The tract is returned from a cache, if available, otherwise generated
        on the fly.
        """
        if index < 0 or index > self._numTracts:
            raise IndexError("Index out of range: %d vs %d" % (index, self._numTracts))
        if self._tractCache[index] is not None:
            return self._tractCache[index]
        tract = self.generateTract(index)
        self._tractCache[index] = tract
        return tract
 

__hash__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__hash__ (   self )

inherited

Definition at line 249 of file baseSkyMap.py.

    def __hash__(self):
        return hash(self.getSha1())
 

__iter__()

def lsst.skymap.cachingSkyMap.CachingSkyMap.__iter__ (   self )

inherited

Iterator over tracts.

Reimplemented from lsst.skymap.baseSkyMap.BaseSkyMap.

Definition at line 71 of file cachingSkyMap.py.

    def __iter__(self):
        """Iterator over tracts."""
        for i in range(self._numTracts):
            yield self[i]
 

__len__()

def lsst.skymap.cachingSkyMap.CachingSkyMap.__len__ (   self )

inherited

Length is number of tracts.

Reimplemented from lsst.skymap.baseSkyMap.BaseSkyMap.

Definition at line 76 of file cachingSkyMap.py.

    def __len__(self):
        """Length is number of tracts."""
        return self._numTracts
 

__ne__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__ne__ (   self,   other  )

inherited

Definition at line 258 of file baseSkyMap.py.

    def __ne__(self, other):
        return not (self == other)
 

__reduce__()

def lsst.skymap.cachingSkyMap.CachingSkyMap.__reduce__ (   self )

inherited

To support pickling.

Notes
-----
**Warning:** This method assumes that the constructor is be defined:
    __init__(self, config, version=defaultVersion)
The use of 'config' is effectively set by the registry mechanism.
If additional optional arguments are added, this method should be
overridden to correspond.

Definition at line 58 of file cachingSkyMap.py.

    def __reduce__(self):
        """To support pickling.
 
        Notes
        -----
        **Warning:** This method assumes that the constructor is be defined:
            __init__(self, config, version=defaultVersion)
        The use of 'config' is effectively set by the registry mechanism.
        If additional optional arguments are added, this method should be
        overridden to correspond.
        """
        return (self.__class__, (self.config, self._version))
 

findClosestTractPatchList()

def lsst.skymap.baseSkyMap.BaseSkyMap.findClosestTractPatchList (   self,   coordList  )

inherited

Find closest tract and patches that overlap coordinates.

Parameters
----------
coordList : `lsst.geom.SpherePoint`
    List of ICRS sky coordinates to search for.

Returns
-------
retList : `list`
    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.

Definition at line 217 of file baseSkyMap.py.

    def findClosestTractPatchList(self, coordList):
        """Find closest tract and patches that overlap coordinates.
 
        Parameters
        ----------
        coordList : `lsst.geom.SpherePoint`
            List of ICRS sky coordinates to search for.
 
        Returns
        -------
        retList : `list`
            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.
        """
        retList = []
        for coord in coordList:
            tractInfo = self.findTract(coord)
            patchList = tractInfo.findPatchList(coordList)
            if patchList and not (tractInfo, patchList) in retList:
                retList.append((tractInfo, patchList))
        return retList
 

findTract()

def lsst.skymap.healpixSkyMap.HealpixSkyMap.findTract	(		self,
			coord
	)

Find the tract whose inner region includes the coord.

Parameters
----------
coord : `lsst.geom.SpherePoint`
    ICRS sky coordinate to search for.

Returns
-------
tractInfo : `TractInfo`
    Info for tract whose inner region includes the coord.

Reimplemented from lsst.skymap.baseSkyMap.BaseSkyMap.

Definition at line 109 of file healpixSkyMap.py.

    def findTract(self, coord):
        """Find the tract whose inner region includes the coord.
 
        Parameters
        ----------
        coord : `lsst.geom.SpherePoint`
            ICRS sky coordinate to search for.
 
        Returns
        -------
        tractInfo : `TractInfo`
            Info for tract whose inner region includes the coord.
        """
        theta, phi = coordToAng(coord)
        index = healpy.ang2pix(self._nside, theta, phi, nest=self.config.nest)
        return self[index]
 

findTractIdArray()

def lsst.skymap.baseSkyMap.BaseSkyMap.findTractIdArray (   self,   ra,   dec,   degrees = False  )

inherited

Find array of tract IDs with vectorized operations (where supported).

If a given sky map does not support vectorized operations, then a loop
over findTract will be called.

Parameters
----------
ra : `np.ndarray`
    Array of Right Ascension.  Units are radians unless
    degrees=True.
dec : `np.ndarray`
    Array of Declination.  Units are radians unless
    degrees=True.
degrees : `bool`, optional
    Input ra, dec arrays are degrees if True.

Returns
-------
tractId : `np.ndarray`
    Array of tract IDs

Notes
-----
- If coord is equidistant between multiple sky tract centers then one
  is arbitrarily chosen.

**Warning:**
If tracts do not cover the whole sky then the returned tract may not
include the given ra/dec.

Reimplemented in lsst.skymap.ringsSkyMap.RingsSkyMap.

Definition at line 150 of file baseSkyMap.py.

    def findTractIdArray(self, ra, dec, degrees=False):
        """Find array of tract IDs with vectorized operations (where supported).
 
        If a given sky map does not support vectorized operations, then a loop
        over findTract will be called.
 
        Parameters
        ----------
        ra : `np.ndarray`
            Array of Right Ascension.  Units are radians unless
            degrees=True.
        dec : `np.ndarray`
            Array of Declination.  Units are radians unless
            degrees=True.
        degrees : `bool`, optional
            Input ra, dec arrays are degrees if True.
 
        Returns
        -------
        tractId : `np.ndarray`
            Array of tract IDs
 
        Notes
        -----
        - If coord is equidistant between multiple sky tract centers then one
          is arbitrarily chosen.
 
        **Warning:**
        If tracts do not cover the whole sky then the returned tract may not
        include the given ra/dec.
        """
        units = geom.degrees if degrees else geom.radians
        coords = [geom.SpherePoint(r*units, d*units) for r, d in zip(np.atleast_1d(ra),
                                                                     np.atleast_1d(dec))]
 
        tractId = np.array([self.findTract(coord).getId() for coord in coords])
 
        return tractId
 

findTractPatchList()

def lsst.skymap.baseSkyMap.BaseSkyMap.findTractPatchList (   self,   coordList  )

inherited

Find tracts and patches that overlap a region.

Parameters
----------
coordList : `list` of `lsst.geom.SpherePoint`
    List of ICRS sky coordinates to search for.

Returns
-------
reList : `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.

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).

Reimplemented in lsst.skymap.ringsSkyMap.RingsSkyMap.

Definition at line 189 of file baseSkyMap.py.

    def findTractPatchList(self, coordList):
        """Find tracts and patches that overlap a region.
 
        Parameters
        ----------
        coordList : `list` of `lsst.geom.SpherePoint`
            List of ICRS sky coordinates to search for.
 
        Returns
        -------
        reList : `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.
 
        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).
        """
        retList = []
        for tractInfo in self:
            patchList = tractInfo.findPatchList(coordList)
            if patchList:
                retList.append((tractInfo, patchList))
        return retList
 

generateTract()

def lsst.skymap.healpixSkyMap.HealpixSkyMap.generateTract	(		self,
			index
	)

Generate TractInfo for the specified tract index.

Reimplemented from lsst.skymap.cachingSkyMap.CachingSkyMap.

Definition at line 126 of file healpixSkyMap.py.

    def generateTract(self, index):
        """Generate TractInfo for the specified tract index."""
        center = angToCoord(healpy.pix2ang(self._nside, index, nest=self.config.nest))
        wcs = self._wcsFactory.makeWcs(crPixPos=geom.Point2D(0, 0), crValCoord=center)
        return HealpixTractInfo(self._nside, index, self.config.nest, self.config.patchInnerDimensions,
                                self.config.patchBorder, center, self.config.tractOverlap*geom.degrees,
                                wcs)
 

getSha1()

def lsst.skymap.baseSkyMap.BaseSkyMap.getSha1 (   self )

inherited

Return a SHA1 hash that uniquely identifies this SkyMap instance.

Returns
-------
sha1 : `bytes`
    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.

Definition at line 285 of file baseSkyMap.py.

    def getSha1(self):
        """Return a SHA1 hash that uniquely identifies this SkyMap instance.
 
        Returns
        -------
        sha1 : `bytes`
            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.
        """
        if self._sha1 is None:
            sha1 = hashlib.sha1()
            sha1.update(type(self).__name__.encode('utf-8'))
            configPacked = struct.pack(
                "<iiidd3sd",
                self.config.patchInnerDimensions[0],
                self.config.patchInnerDimensions[1],
                self.config.patchBorder,
                self.config.tractOverlap,
                self.config.pixelScale,
                self.config.projection.encode('ascii'),
                self.config.rotation
            )
            sha1.update(configPacked)
            self.updateSha1(sha1)
            self._sha1 = sha1.digest()
        return self._sha1
 

logSkyMapInfo()

def lsst.skymap.baseSkyMap.BaseSkyMap.logSkyMapInfo (   self,   log  )

inherited

Write information about a sky map to supplied log

Parameters
----------
log : `lsst.log.Log`
    Log object that information about skymap will be written

Definition at line 261 of file baseSkyMap.py.

    def logSkyMapInfo(self, log):
        """Write information about a sky map to supplied log
 
        Parameters
        ----------
        log : `lsst.log.Log`
            Log object that information about skymap will be written
        """
        log.info("sky map has %s tracts" % (len(self),))
        for tractInfo in self:
            wcs = tractInfo.getWcs()
            posBox = geom.Box2D(tractInfo.getBBox())
            pixelPosList = (
                posBox.getMin(),
                geom.Point2D(posBox.getMaxX(), posBox.getMinY()),
                posBox.getMax(),
                geom.Point2D(posBox.getMinX(), posBox.getMaxY()),
            )
            skyPosList = [wcs.pixelToSky(pos).getPosition(geom.degrees) for pos in pixelPosList]
            posStrList = ["(%0.3f, %0.3f)" % tuple(skyPos) for skyPos in skyPosList]
            log.info("tract %s has corners %s (RA, Dec deg) and %s x %s patches" %
                     (tractInfo.getId(), ", ".join(posStrList),
                      tractInfo.getNumPatches()[0], tractInfo.getNumPatches()[1]))
 

register()

def lsst.skymap.baseSkyMap.BaseSkyMap.register (   self,   name,   butler  )

inherited

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

Parameters
----------
name : `str`
    The name of the skymap.
butler : `lsst.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.

Definition at line 337 of file baseSkyMap.py.

    def register(self, name, butler):
        """Add skymap, tract, and patch Dimension entries to the given Gen3
        Butler.
 
        Parameters
        ----------
        name : `str`
            The name of the skymap.
        butler : `lsst.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.
        """
        nxMax = 0
        nyMax = 0
        tractRecords = []
        patchRecords = []
        for tractInfo in self:
            nx, ny = tractInfo.getNumPatches()
            nxMax = max(nxMax, nx)
            nyMax = max(nyMax, ny)
            region = tractInfo.getOuterSkyPolygon()
            centroid = SpherePoint(region.getCentroid())
            tractRecords.append({
                "skymap": name,
                "tract": tractInfo.getId(),
                "region": region,
                "ra": centroid.getRa().asDegrees(),
                "dec": centroid.getDec().asDegrees(),
            })
            for patchInfo in tractInfo:
                cellX, cellY = patchInfo.getIndex()
                patchRecords.append({
                    "skymap": name,
                    "tract": tractInfo.getId(),
                    "patch": tractInfo.getSequentialPatchIndex(patchInfo),
                    "cell_x": cellX,
                    "cell_y": cellY,
                    "region": patchInfo.getOuterSkyPolygon(tractInfo.getWcs()),
                })
        skyMapRecord = {
            "skymap": name,
            "hash": self.getSha1(),
            "tract_max": len(self),
            "patch_nx_max": nxMax,
            "patch_ny_max": nyMax,
        }
        butler.registry.registerRun(self.SKYMAP_RUN_COLLECTION_NAME)
        # Kind of crazy that we've got three different capitalizations of
        # "skymap" here, but that's what the various conventions (or at least
        # precedents) dictate.
        from lsst.daf.butler import DatasetType
        from lsst.daf.butler.registry import ConflictingDefinitionError
        datasetType = DatasetType(
            name=self.SKYMAP_DATASET_TYPE_NAME,
            dimensions=["skymap"],
            storageClass="SkyMap",
            universe=butler.registry.dimensions
        )
        butler.registry.registerDatasetType(datasetType)
        with butler.transaction():
            try:
                inserted = butler.registry.syncDimensionData("skymap", skyMapRecord)
            except ConflictingDefinitionError as err:
                raise ConflictingDefinitionError(
                    f"SkyMap with hash {self.getSha1().hex()} is already registered with a different name."
                ) from err
            if inserted:
                butler.registry.insertDimensionData("tract", *tractRecords)
                butler.registry.insertDimensionData("patch", *patchRecords)
                butler.put(self, datasetType, {"skymap": name}, run=self.SKYMAP_RUN_COLLECTION_NAME)

updateSha1()

def lsst.skymap.healpixSkyMap.HealpixSkyMap.updateSha1	(		self,
			sha1
	)

Add subclass-specific state or configuration options to the SHA1.

Reimplemented from lsst.skymap.baseSkyMap.BaseSkyMap.

Definition at line 134 of file healpixSkyMap.py.

    def updateSha1(self, sha1):
        """Add subclass-specific state or configuration options to the SHA1."""
        sha1.update(struct.pack("<i?", self.config.log2NSide, self.config.nest))

Member Data Documentation

config

lsst.skymap.baseSkyMap.BaseSkyMap.config

inherited

Definition at line 108 of file baseSkyMap.py.

ConfigClass

lsst.skymap.healpixSkyMap.HealpixSkyMap.ConfigClass = HealpixSkyMapConfig

static

Definition at line 100 of file healpixSkyMap.py.

numAngles

int lsst.skymap.healpixSkyMap.HealpixSkyMap.numAngles = 4

static

Definition at line 102 of file healpixSkyMap.py.

SKYMAP_DATASET_TYPE_NAME

string lsst.skymap.baseSkyMap.BaseSkyMap.SKYMAP_DATASET_TYPE_NAME = "skyMap"

staticinherited

Definition at line 335 of file baseSkyMap.py.

SKYMAP_RUN_COLLECTION_NAME

string lsst.skymap.baseSkyMap.BaseSkyMap.SKYMAP_RUN_COLLECTION_NAME = "skymaps"

staticinherited

Definition at line 333 of file baseSkyMap.py.

---

The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-0.7.0/Linux64/skymap/22.0.1-4-g037fbe1+64e601228d/python/lsst/skymap/healpixSkyMap.py