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	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, registry)

Public Attributes
	config

Static Public Attributes
	ConfigClass
	numAngles

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 212 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 209 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 218 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 177 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]
 

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 149 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 245 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 221 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,   registry  )

inherited

Add SkyMap, Tract, and Patch Dimension entries to the given Gen3
Butler Registry.

Parameters
----------
name : `str`
    The name of the skymap.
registry : `lsst.daf.butler.Registry`
    The registry to add to.

Definition at line 293 of file baseSkyMap.py.

    def register(self, name, registry):
        """Add SkyMap, Tract, and Patch Dimension entries to the given Gen3
        Butler Registry.
 
        Parameters
        ----------
        name : `str`
            The name of the skymap.
        registry : `lsst.daf.butler.Registry`
            The registry to add to.
        """
        nxMax = 0
        nyMax = 0
        records = {
            "skymap": [],
            "tract": [],
            "patch": [],
        }
        for tractInfo in self:
            nx, ny = tractInfo.getNumPatches()
            nxMax = max(nxMax, nx)
            nyMax = max(nyMax, ny)
            region = tractInfo.getOuterSkyPolygon()
            centroid = SpherePoint(region.getCentroid())
            records["tract"].append({
                "skymap": name,
                "tract": tractInfo.getId(),
                "region": region,
                "ra": centroid.getRa().asDegrees(),
                "dec": centroid.getDec().asDegrees(),
            })
            for patchInfo in tractInfo:
                cellX, cellY = patchInfo.getIndex()
                records["patch"].append({
                    "skymap": name,
                    "tract": tractInfo.getId(),
                    "patch": tractInfo.getSequentialPatchIndex(patchInfo),
                    "cell_x": cellX,
                    "cell_y": cellY,
                    "region": patchInfo.getOuterSkyPolygon(tractInfo.getWcs()),
                })
        records["skymap"].append({
            "skymap": name,
            "hash": self.getSha1(),
            "tract_max": len(self),
            "patch_nx_max": nxMax,
            "patch_ny_max": nyMax,
        })
        with registry.transaction():
            for dimension, recordsForDimension in records.items():
                registry.insertDimensionData(dimension, *recordsForDimension)

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 107 of file baseSkyMap.py.

ConfigClass

lsst.skymap.healpixSkyMap.HealpixSkyMap.ConfigClass

static

Definition at line 100 of file healpixSkyMap.py.

numAngles

lsst.skymap.healpixSkyMap.HealpixSkyMap.numAngles

static

Definition at line 102 of file healpixSkyMap.py.

---

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

• /j/snowflake/release/lsstsw/stack/1a1d771/Linux64/skymap/20.0.0/python/lsst/skymap/healpixSkyMap.py