23__all__ = [
"TractInfo"]
31from .patchInfo
import PatchInfo, makeSkyPolygonFromBBox
35 """Information about a tract in a SkyMap sky pixelization
41 patchInnerDimensions : `tuple` of `int`
42 Dimensions of inner region of patches (x,y pixels).
44 Overlap between adjacent patches (in pixels)
46 ICRS sky coordinate of center of inner region of tract; also used
as
47 the CRVAL
for the WCS.
49 Vertices that define the boundaries of the inner region.
51 Minimum overlap between adjacent sky tracts; this defines the minimum
52 distance the tract extends beyond the inner region
in all directions.
53 wcs : `lsst.afw.image.SkyWcs`
54 WCS
for tract. The reference pixel will be shifted
as required so that
55 the lower left-hand pixel (index 0,0) has pixel position 0.0, 0.0.
59 The tract
is subdivided into rectangular patches. Each patch has the
62 - An inner region defined by an inner bounding box. The inner regions of
63 the patches exactly tile the tract,
and all inner regions have the same
64 dimensions. The tract
is made larger
as required to make this work.
66 - An outer region defined by an outer bounding box. The outer region
67 extends beyond the inner region by patchBorder pixels
in all directions,
68 except there
is no border at the edges of the tract.
69 Thus patches overlap each other but never extend off the tract.
70 If you do
not want any overlap between adjacent patches then set
73 - An index that consists of a pair of integers:
75 * 0 <= x index < numPatches[0]
77 * 0 <= y index < numPatches[1]
79 Patch 0,0
is at the minimum corner of the tract bounding box.
81 - It
is not enforced that ctrCoord
is the center of vertexCoordList, but
85 def __init__(self, id, patchInnerDimensions, patchBorder, ctrCoord, vertexCoordList, tractOverlap, wcs):
88 assert len(patchInnerDimensions) == 2
91 raise TypeError(
"patchInnerDimensions=%s; must be two ints" % (patchInnerDimensions,))
101 def _minimumBoundingBox(self, wcs):
102 """Calculate the minimum bounding box for the tract, given the WCS.
104 The bounding box is created
in the frame of the supplied WCS,
105 so that it
's OK if the coordinates are negative.
107 We compute the bounding box that holds all the vertices and the
114 minBBoxD.include(wcs.skyToPixel(vertexCoord))
117 angleIncr =
geom.Angle(360.0, geom.degrees) / float(numAngles)
118 for i
in range(numAngles):
119 offAngle = angleIncr * i
120 offCoord = vertexCoord.offset(offAngle, halfOverlap)
121 pixPos = wcs.skyToPixel(offCoord)
122 minBBoxD.include(pixPos)
125 def _setupPatches(self, minBBox, wcs):
126 """Setup for patches of a particular size.
128 We grow the bounding box to hold an exact multiple of
129 the desired size (patchInnerDimensions), while keeping
130 the center roughly the same. We
return the final
131 bounding box,
and the number of patches
in each dimension
137 Minimum bounding box
for tract
144 final bounding box, number of patches
148 bboxMin = bbox.getMin()
149 bboxDim = bbox.getDimensions()
152 num = (bboxDim[i] + innerDim - 1) // innerDim
153 deltaDim = (innerDim * num) - bboxDim[i]
155 bboxDim[i] = innerDim * num
156 bboxMin[i] -= deltaDim // 2
159 return bbox, numPatches
161 def _finalOrientation(self, bbox, wcs):
162 """Determine the final orientation
164 We offset everything so the lower-left corner is at 0,0
165 and compute the final Wcs.
170 Current bounding box.
177 Revised bounding box.
184 pixPosOffset =
geom.Extent2D(finalBBox.getMinX() - bbox.getMinX(),
185 finalBBox.getMinY() - bbox.getMinY())
186 wcs = wcs.copyAtShiftedPixelOrigin(pixPosOffset)
187 return finalBBox, wcs
190 """Return a single integer that uniquely identifies the given patch
193 x, y = patchInfo.getIndex()
199 x = sequentialIndex % nx
200 y = (sequentialIndex - x) // nx
204 """Find the patch containing the specified coord.
209 ICRS sky coordinate to search for.
214 PatchInfo of patch whose inner bbox contains the specified coord
219 If coord
is not in tract
or we cannot determine the
220 pixel coordinate (which likely means the coord
is off the tract).
223 pixel = self.
getWcs().skyToPixel(coord)
226 raise LookupError(
"Unable to determine pixel position for coordinate %s" % (coord,))
229 raise LookupError(
"coord %s is not in tract %s" % (coord, self.
getId()))
234 """Find patches containing the specified list of coords.
239 ICRS sky coordinates to search for.
244 List of PatchInfo
for patches that contain,
or may contain, the
245 specified region. The list will be empty
if there
is no overlap.
251 - This may give incorrect answers on regions that are larger than a
254 - This uses a naive algorithm that may find some patches that do
not
255 overlap the region (especially
if the region
is not a rectangle
256 aligned along patch x,y).
259 for coord
in coordList:
261 pixelPos = self.
getWcs().skyToPixel(coord)
265 box2D.include(pixelPos)
275 for xInd
in range(llPatchInd[0], urPatchInd[0]+1)
276 for yInd
in range(llPatchInd[1], urPatchInd[1]+1))
279 """Get bounding box of tract (as an geom.Box2I)
284 """Get ICRS sky coordinate of center of tract
295 """Get the number of patches in x, y.
299 result : `tuple` of `int`
300 The number of patches in x, y
308 """Return information for the specified patch.
312 index : `tuple` of `int`
313 Index of patch, as a pair of ints;
314 or a sequential index
as returned by getSequentialPatchIndex;
315 negative values are
not supported.
320 The patch info
for that index.
325 If index
is out of range.
327 if isinstance(index, numbers.Number):
331 raise IndexError(
"Patch index %s is not in range [0-%d, 0-%d]" %
335 if not self._bbox.
contains(innerBBox):
337 "Bug: patch index %s valid but inner bbox=%s not contained in tract bbox=%s" %
338 (index, innerBBox, self._bbox))
341 outerBBox.clip(self._bbox)
349 """Get dimensions of inner region of the patches (all are the same)
354 """Get minimum overlap of adjacent sky tracts.
359 """Get list of ICRS sky coordinates of vertices that define the
360 boundary of the inner region.
364 **warning:** this is not a deep copy.
369 """Get inner on-sky region as a sphgeom.ConvexPolygon.
371 skyUnitVectors = [sp.getVector() for sp
in self.
getVertexList()]
372 return ConvexPolygon.convexHull(skyUnitVectors)
375 """Get outer on-sky region as a sphgeom.ConvexPolygon
377 return makeSkyPolygonFromBBox(bbox=self.
getBBox(), wcs=self.
getWcs())
385 The WCS of this tract
390 return "TractInfo(id=%s)" % (self.
_id,)
393 return "TractInfo(id=%s, ctrCoord=%s)" % (self.
_id, self.
_ctrCoord.getVector())
397 for y
in range(yNum):
398 for x
in range(xNum):
409 """Does this tract contain the coordinate?"""
411 pixels = self.
getWcs().skyToPixel(coord)
419 """Information for a tract specified explicitly.
421 A tract is placed at the explicitly defined coordinates,
with the nominated
422 radius. The tracts are square (i.e., the radius
is really a half-size).
425 def __init__(self, ident, patchInnerDimensions, patchBorder, ctrCoord, radius, tractOverlap, wcs):
429 super(ExplicitTractInfo, self).
__init__(ident, patchInnerDimensions, patchBorder, ctrCoord,
430 vertexList, tractOverlap, wcs)
437 def _minimumBoundingBox(self, wcs):
438 """Calculate the minimum bounding box for the tract, given the WCS, and
439 the nominated radius.
444 pixPos = wcs.skyToPixel(cornerCoord)
def __init__(self, ident, patchInnerDimensions, patchBorder, ctrCoord, radius, tractOverlap, wcs)
def getTractOverlap(self)
def _finalOrientation(self, bbox, wcs)
def getSequentialPatchIndex(self, patchInfo)
def findPatchList(self, coordList)
def __init__(self, id, patchInnerDimensions, patchBorder, ctrCoord, vertexCoordList, tractOverlap, wcs)
def getPatchInfo(self, index)
def __getitem__(self, index)
def getInnerSkyPolygon(self)
def contains(self, coord)
def getPatchIndexPair(self, sequentialIndex)
def getPatchInnerDimensions(self)
def _setupPatches(self, minBBox, wcs)
def getOuterSkyPolygon(self)
def findPatch(self, coord)
def _minimumBoundingBox(self, wcs)