23 todo: Consider tweaking pixel scale so the average scale is as specified,
24 rather than the scale at the center.
27 __all__ = [
"BaseSkyMapConfig",
"BaseSkyMap"]
34 from lsst.geom import SpherePoint, Angle, arcseconds, degrees
39 patchInnerDimensions = pexConfig.ListField(
40 doc=
"dimensions of inner region of patches (x,y pixels)",
45 patchBorder = pexConfig.Field(
46 doc=
"border between patch inner and outer bbox (pixels)",
50 tractOverlap = pexConfig.Field(
51 doc=
"minimum overlap between adjacent sky tracts, on the sky (deg)",
55 pixelScale = pexConfig.Field(
56 doc=
"nominal pixel scale (arcsec/pixel)",
60 projection = pexConfig.Field(
61 doc=
"one of the FITS WCS projection codes, such as:"
62 "- STG: stereographic projection"
63 "- MOL: Molleweide's projection"
64 "- TAN: tangent-plane projection",
68 rotation = pexConfig.Field(
69 doc=
"Rotation for WCS (deg)",
76 """A collection of overlapping Tracts that map part or all of the sky.
78 See TractInfo for more information.
82 config : `BaseSkyMapConfig` or None (optional)
83 The configuration for this SkyMap; if None use the default config.
87 BaseSkyMap is an abstract base class. Subclasses must do the following:
88 define ``__init__`` and have it construct the TractInfo objects and put
89 them in ``__tractInfoList__`` define ``__getstate__`` and ``__setstate__``
90 to allow pickling (the butler saves sky maps using pickle);
91 see DodecaSkyMap for an example of how to do this. (Most of that code could
92 be moved into this base class, but that would make it harder to handle
93 older versions of pickle data.) define updateSha1 to add any
94 subclass-specific state to the hash.
96 All SkyMap subclasses must be conceptually immutable; they must always
97 refer to the same set of mathematical tracts and patches even if the in-
98 memory representation of those objects changes.
101 ConfigClass = BaseSkyMapConfig
110 pixelScale=
Angle(self.
config.pixelScale, arcseconds),
111 projection=self.
config.projection,
117 """Find the tract whose center is nearest the specified coord.
121 coord : `lsst.geom.SpherePoint`
122 ICRS sky coordinate to search for.
127 TractInfo of tract whose center is nearest the specified coord.
131 - If coord is equidistant between multiple sky tract centers then one
132 is arbitrarily chosen.
134 - The default implementation is not very efficient; subclasses may wish
138 If tracts do not cover the whole sky then the returned tract may not
141 distTractInfoList = []
142 for i, tractInfo
in enumerate(self):
143 angSep = coord.separation(tractInfo.getCtrCoord()).asDegrees()
145 distTractInfoList.append((angSep, i, tractInfo))
146 distTractInfoList.sort()
147 return distTractInfoList[0][2]
150 """Find tracts and patches that overlap a region.
154 coordList : `list` of `lsst.geom.SpherePoint`
155 List of ICRS sky coordinates to search for.
159 reList : `list` of (`TractInfo`, `list` of `PatchInfo`)
160 For tracts and patches that contain, or may contain, the specified
161 region. The list will be empty if there is no overlap.
166 This uses a naive algorithm that may find some tracts and patches
167 that do not overlap the region (especially if the region is not a
168 rectangle aligned along patch x, y).
171 for tractInfo
in self:
172 patchList = tractInfo.findPatchList(coordList)
174 retList.append((tractInfo, patchList))
178 """Find closest tract and patches that overlap coordinates.
182 coordList : `lsst.geom.SpherePoint`
183 List of ICRS sky coordinates to search for.
188 list of (TractInfo, list of PatchInfo) for tracts and patches
189 that contain, or may contain, the specified region.
190 The list will be empty if there is no overlap.
193 for coord
in coordList:
195 patchList = tractInfo.findPatchList(coordList)
196 if patchList
and not (tractInfo, patchList)
in retList:
197 retList.append((tractInfo, patchList))
214 return self.
getSha1() == other.getSha1()
215 except AttributeError:
216 return NotImplemented
219 return not (self == other)
222 """Write information about a sky map to supplied log
227 Log object that information about skymap will be written
229 log.info(
"sky map has %s tracts" % (len(self),))
230 for tractInfo
in self:
231 wcs = tractInfo.getWcs()
239 skyPosList = [wcs.pixelToSky(pos).getPosition(geom.degrees)
for pos
in pixelPosList]
240 posStrList = [
"(%0.3f, %0.3f)" % tuple(skyPos)
for skyPos
in skyPosList]
241 log.info(
"tract %s has corners %s (RA, Dec deg) and %s x %s patches" %
242 (tractInfo.getId(),
", ".join(posStrList),
243 tractInfo.getNumPatches()[0], tractInfo.getNumPatches()[1]))
246 """Return a SHA1 hash that uniquely identifies this SkyMap instance.
251 A 20-byte hash that uniquely identifies this SkyMap instance.
255 Subclasses should almost always override ``updateSha1`` instead of
256 this function to add subclass-specific state to the hash.
258 if self.
_sha1 is None:
259 sha1 = hashlib.sha1()
260 sha1.update(type(self).__name__.encode(
'utf-8'))
261 configPacked = struct.pack(
263 self.
config.patchInnerDimensions[0],
264 self.
config.patchInnerDimensions[1],
268 self.
config.projection.encode(
'ascii'),
271 sha1.update(configPacked)
273 self.
_sha1 = sha1.digest()
277 """Add subclass-specific state or configuration options to the SHA1.
281 sha1 : `hashlib.sha1`
282 A hashlib object on which `update` can be called to add
283 additional state to the hash.
287 This method is conceptually "protected" : it should be reimplemented by
288 all subclasses, but called only by the base class implementation of
291 raise NotImplementedError()
294 """Add skymap, tract, and patch Dimension entries to the given Gen3
300 The name of the skymap.
301 registry : `lsst.daf.butler.Registry`
302 The registry to add to.
306 lsst.daf.butler.registry.ConflictingDefinitionError
307 Raised if a different skymap exists with the same name.
311 Registering the same skymap multiple times (with the exact same
312 definition) is safe, but inefficient; most of the work of computing
313 the rows to be inserted must be done first in order to check for
314 consistency between the new skymap and any existing one.
316 Re-registering a skymap with different tract and/or patch definitions
317 but the same summary information may not be detected as a conflict but
318 will never result in updating the skymap; there is intentionally no
319 way to modify a registered skymap (aside from manual administrative
320 operations on the database), as it is hard to guarantee that this can
321 be done without affecting reproducibility.
327 for tractInfo
in self:
328 nx, ny = tractInfo.getNumPatches()
329 nxMax = max(nxMax, nx)
330 nyMax = max(nyMax, ny)
331 region = tractInfo.getOuterSkyPolygon()
333 tractRecords.append({
335 "tract": tractInfo.getId(),
337 "ra": centroid.getRa().asDegrees(),
338 "dec": centroid.getDec().asDegrees(),
340 for patchInfo
in tractInfo:
341 cellX, cellY = patchInfo.getIndex()
342 patchRecords.append({
344 "tract": tractInfo.getId(),
345 "patch": tractInfo.getSequentialPatchIndex(patchInfo),
348 "region": patchInfo.getOuterSkyPolygon(tractInfo.getWcs()),
353 "tract_max": len(self),
354 "patch_nx_max": nxMax,
355 "patch_ny_max": nyMax,
357 with registry.transaction():
358 if registry.syncDimensionData(
"skymap", skyMapRecord):
359 registry.insertDimensionData(
"tract", *tractRecords)
360 registry.insertDimensionData(
"patch", *patchRecords)