lsst.skymap.baseSkyMap.BaseSkyMap Class Reference

Inheritance diagram for lsst.skymap.baseSkyMap.BaseSkyMap:

Public Member Functions
def	__init__ (self, config=None)
def	findTract (self, coord)
def	findTractIdArray (self, ra, dec, degrees=False)
def	findTractPatchList (self, coordList)
def	findClosestTractPatchList (self, coordList)
def	__getitem__ (self, ind)
def	__iter__ (self)
def	__len__ (self)
def	__hash__ (self)
def	__eq__ (self, other)
def	__ne__ (self, other)
def	logSkyMapInfo (self, log)
def	getSha1 (self)
def	updateSha1 (self, sha1)
def	register (self, name, butler)

Public Attributes
	config

Static Public Attributes
	ConfigClass = BaseSkyMapConfig
string	SKYMAP_RUN_COLLECTION_NAME = "skymaps"
string	SKYMAP_DATASET_TYPE_NAME = "skyMap"

Detailed Description

A collection of overlapping Tracts that map part or all of the sky.

See TractInfo for more information.

Parameters
----------
config : `BaseSkyMapConfig` or None (optional)
    The configuration for this SkyMap; if None use the default config.

Notes
-----
BaseSkyMap is an abstract base class. Subclasses must do the following:
define ``__init__`` and have it construct the TractInfo objects and put
them in ``__tractInfoList__`` define ``__getstate__`` and ``__setstate__``
to allow pickling (the butler saves sky maps using pickle);
see DodecaSkyMap for an example of how to do this. (Most of that code could
be moved into this base class, but that would make it harder to handle
older versions of pickle data.) define updateSha1 to add any
subclass-specific state to the hash.

All SkyMap subclasses must be conceptually immutable; they must always
refer to the same set of mathematical tracts and patches even if the in-
memory representation of those objects changes.

Definition at line 76 of file baseSkyMap.py.

Constructor & Destructor Documentation

__init__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__init__	(		self,
			config = None
	)

Reimplemented in lsst.skymap.equatSkyMap.EquatSkyMap, and lsst.skymap.dodecaSkyMap.DodecaSkyMap.

Definition at line 104 of file baseSkyMap.py.

    def __init__(self, config=None):
        if config is None:
            config = self.ConfigClass()
        config.freeze()  # just to be sure, e.g. for pickling
        self.config = config
        self._tractInfoList = []
        self._wcsFactory = detail.WcsFactory(
            pixelScale=Angle(self.config.pixelScale, arcseconds),
            projection=self.config.projection,
            rotation=Angle(self.config.rotation, degrees),
        )
        self._sha1 = None
 

Member Function Documentation

__eq__()

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

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.baseSkyMap.BaseSkyMap.__getitem__	(		self,
			ind
	)

Reimplemented in lsst.skymap.cachingSkyMap.CachingSkyMap.

Definition at line 240 of file baseSkyMap.py.

    def __getitem__(self, ind):
        return self._tractInfoList[ind]
 

__hash__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__hash__

(

self

)

Definition at line 249 of file baseSkyMap.py.

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

__iter__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__iter__

(

self

)

Reimplemented in lsst.skymap.cachingSkyMap.CachingSkyMap.

Definition at line 243 of file baseSkyMap.py.

    def __iter__(self):
        return iter(self._tractInfoList)
 

__len__()

def lsst.skymap.baseSkyMap.BaseSkyMap.__len__

(

self

)

Reimplemented in lsst.skymap.cachingSkyMap.CachingSkyMap.

Definition at line 246 of file baseSkyMap.py.

    def __len__(self):
        return len(self._tractInfoList)
 

__ne__()

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

Definition at line 258 of file baseSkyMap.py.

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

findClosestTractPatchList()

def lsst.skymap.baseSkyMap.BaseSkyMap.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.

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.baseSkyMap.BaseSkyMap.findTract	(		self,
			coord
	)

Find the tract whose center is nearest the specified coord.

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

Returns
-------
result : `TractInfo`
    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.

Reimplemented in lsst.skymap.ringsSkyMap.RingsSkyMap, lsst.skymap.healpixSkyMap.HealpixSkyMap, and lsst.skymap.dodecaSkyMap.DodecaSkyMap.

Definition at line 117 of file baseSkyMap.py.

    def findTract(self, coord):
        """Find the tract whose center is nearest the specified coord.
 
        Parameters
        ----------
        coord : `lsst.geom.SpherePoint`
            ICRS sky coordinate to search for.
 
        Returns
        -------
        result : `TractInfo`
            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.
        """
        distTractInfoList = []
        for i, tractInfo in enumerate(self):
            angSep = coord.separation(tractInfo.getCtrCoord()).asDegrees()
            # include index in order to disambiguate identical angSep values
            distTractInfoList.append((angSep, i, tractInfo))
        distTractInfoList.sort()
        return distTractInfoList[0][2]
 

findTractIdArray()

def lsst.skymap.baseSkyMap.BaseSkyMap.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.

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
	)

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
 

getSha1()

def lsst.skymap.baseSkyMap.BaseSkyMap.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.

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
	)

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
	)

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.baseSkyMap.BaseSkyMap.updateSha1	(		self,
			sha1
	)

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

Parameters
----------
sha1 : `hashlib.sha1`
    A hashlib object on which `update` can be called to add
    additional state to the hash.

Notes
-----
This method is conceptually "protected" : it should be reimplemented by
all subclasses, but called only by the base class implementation of
`getSha1` .

Reimplemented in lsst.skymap.ringsSkyMap.RingsSkyMap, lsst.skymap.healpixSkyMap.HealpixSkyMap, lsst.skymap.equatSkyMap.EquatSkyMap, lsst.skymap.dodecaSkyMap.DodecaSkyMap, and lsst.skymap.discreteSkyMap.DiscreteSkyMap.

Definition at line 316 of file baseSkyMap.py.

    def updateSha1(self, sha1):
        """Add subclass-specific state or configuration options to the SHA1.
 
        Parameters
        ----------
        sha1 : `hashlib.sha1`
            A hashlib object on which `update` can be called to add
            additional state to the hash.
 
        Notes
        -----
        This method is conceptually "protected" : it should be reimplemented by
        all subclasses, but called only by the base class implementation of
        `getSha1` .
        """
        raise NotImplementedError()
 

Member Data Documentation

config

lsst.skymap.baseSkyMap.BaseSkyMap.config

Definition at line 108 of file baseSkyMap.py.

ConfigClass

lsst.skymap.baseSkyMap.BaseSkyMap.ConfigClass = BaseSkyMapConfig

static

Definition at line 102 of file baseSkyMap.py.

SKYMAP_DATASET_TYPE_NAME

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

static

Definition at line 335 of file baseSkyMap.py.

SKYMAP_RUN_COLLECTION_NAME

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

static

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/baseSkyMap.py