1 from __future__
import division
2 from builtins
import range
3 from builtins
import object
29 from .patchInfo
import PatchInfo
31 __all__ = [
"TractInfo"]
35 """Information about a tract in a SkyMap sky pixelization 37 The tract is subdivided into rectangular patches. Each patch has the following properties: 38 - An inner region defined by an inner bounding. The inner regions of the patches exactly tile the tract, 39 and all inner regions have the same dimensions. The tract is made larger as required to make this work. 40 - An outer region defined by an outer bounding box. The outer region extends beyond the inner region 41 by patchBorder pixels in all directions, except there is no border at the edges of the tract. 42 Thus patches overlap each other but never extend off the tract. If you do not want any overlap 43 between adjacent patches then set patchBorder to 0. 44 - An index that consists of a pair of integers: 45 0 <= x index < numPatches[0] 46 0 <= y index < numPatches[1] 47 Patch 0,0 is at the minimum corner of the tract bounding box. 50 def __init__(self, id, patchInnerDimensions, patchBorder, ctrCoord, vertexCoordList, tractOverlap, wcs):
51 """Construct a TractInfo 53 @param[in] id: tract ID 54 @param[in] patchInnerDimensions: dimensions of inner region of patches (x,y pixels) 55 @param[in] patchBorder: overlap between adjacent patches (in pixels, one int) 56 @param[in] ctrCoord: sky coordinate of center of inner region of tract, as an afwCoord.Coord; 57 also used as the CRVAL for the WCS. 58 @param[in] vertexCoordList: list of sky coordinates (afwCoord.Coord) 59 of vertices that define the boundaries of the inner region 60 @param[in] tractOverlap: minimum overlap between adjacent sky tracts; an afwGeom.Angle; 61 this defines the minimum distance the tract extends beyond the inner region in all directions 62 @param[in,out] wcs: an afwImage.Wcs; the reference pixel will be shifted as required 63 so that the lower left-hand pixel (index 0,0) has pixel position 0.0, 0.0 66 - It is not enforced that ctrCoord is the center of vertexCoordList, but SkyMap relies on it 67 - vertexCoordList will likely become a geom SphericalConvexPolygon someday. 71 assert len(patchInnerDimensions) == 2
74 raise TypeError(
"patchInnerDimensions=%s; must be two ints" % (patchInnerDimensions,))
84 def _minimumBoundingBox(self, wcs):
85 """Calculate the minimum bounding box for the tract, given the WCS 87 The bounding box is created in the frame of the supplied WCS, 88 so that it's OK if the coordinates are negative. 90 We compute the bounding box that holds all the vertices and the 93 minBBoxD = afwGeom.Box2D()
96 vertexDeg = vertexCoord.getPosition(afwGeom.degrees)
98 minBBoxD.include(wcs.skyToPixel(vertexCoord))
101 angleIncr = afwGeom.Angle(360.0, afwGeom.degrees) / float(numAngles)
102 for i
in range(numAngles):
103 offAngle = angleIncr * i
104 offCoord = vertexCoord.clone()
105 offCoord.offset(offAngle, halfOverlap)
106 pixPos = wcs.skyToPixel(offCoord)
107 minBBoxD.include(pixPos)
110 def _setupPatches(self, minBBox, wcs):
111 """Setup for patches of a particular size. 113 We grow the bounding box to hold an exact multiple of 114 the desired size (patchInnerDimensions), while keeping 115 the center roughly the same. We return the final 116 bounding box, and the number of patches in each dimension 119 @param minBBox Minimum bounding box for tract 120 @param wcs Wcs object 121 @return final bounding box, number of patches 123 bbox = afwGeom.Box2I(minBBox)
124 bboxMin = bbox.getMin()
125 bboxDim = bbox.getDimensions()
126 numPatches = afwGeom.Extent2I(0, 0)
128 num = (bboxDim[i] + innerDim - 1) // innerDim
129 deltaDim = (innerDim * num) - bboxDim[i]
131 bboxDim[i] = innerDim * num
132 bboxMin[i] -= deltaDim // 2
134 bbox = afwGeom.Box2I(bboxMin, bboxDim)
135 return bbox, numPatches
137 def _finalOrientation(self, bbox, wcs):
138 """Determine the final orientation 140 We offset everything so the lower-left corner is at 0,0 141 and compute the final Wcs. 143 @param bbox Current bounding box 144 @param wcs Current Wcs 145 @return revised bounding box, revised Wcs 147 finalBBox = afwGeom.Box2I(afwGeom.Point2I(0, 0), bbox.getDimensions())
150 pixPosOffset = afwGeom.Extent2D(finalBBox.getMinX() - bbox.getMinX(),
151 finalBBox.getMinY() - bbox.getMinY())
152 wcs.shiftReferencePixel(pixPosOffset)
153 return finalBBox, wcs
156 """Find the patch containing the specified coord 158 @param[in] coord: sky coordinate (afwCoord.Coord) 159 @return PatchInfo of patch whose inner bbox contains the specified coord 161 @raise LookupError if coord is not in tract or we cannot determine the 162 pixel coordinate (which likely means the coord is off the tract). 164 @note This routine will be more efficient if coord is ICRS. 166 icrsCoord = coord.toIcrs()
168 pixel = self.
getWcs().skyToPixel(icrsCoord)
171 raise LookupError(
"Unable to determine pixel position for coordinate %s" % (coord,))
172 pixelInd = afwGeom.Point2I(pixel)
174 raise LookupError(
"coord %s is not in tract %s" % (coord, self.
getId()))
179 """Find patches containing the specified list of coords 181 @param[in] coordList: list of sky coordinates (afwCoord.Coord) 182 @return list of PatchInfo for patches that contain, or may contain, the specified region. 183 The list will be empty if there is no overlap. 186 * This may give incorrect answers on regions that are larger than a tract 187 * This uses a naive algorithm that may find some patches that do not overlap the region 188 (especially if the region is not a rectangle aligned along patch x,y). 190 box2D = afwGeom.Box2D()
191 for coord
in coordList:
192 icrsCoord = coord.toIcrs()
194 pixelPos = self.
getWcs().skyToPixel(icrsCoord)
198 box2D.include(pixelPos)
199 bbox = afwGeom.Box2I(box2D)
208 for xInd
in range(llPatchInd[0], urPatchInd[0]+1)
209 for yInd
in range(llPatchInd[1], urPatchInd[1]+1))
212 """Get bounding box of tract (as an afwGeom.Box2I) 214 return afwGeom.Box2I(self._bbox)
217 """Get sky coordinate of center of tract (as an afwCoord.Coord) 227 """Get the number of patches in x, y 229 @return the number of patches in x, y 236 @return patch border (pixels) 241 """Return information for the specified patch 243 @param[in] index: index of patch, as a pair of ints 244 @return patch info, an instance of PatchInfo 246 @raise IndexError if index is out of range 250 raise IndexError(
"Patch index %s is not in range [0-%d, 0-%d]" %
254 if not self._bbox.
contains(innerBBox):
256 "Bug: patch index %s valid but inner bbox=%s not contained in tract bbox=%s" %
257 (index, innerBBox, self._bbox))
258 outerBBox = afwGeom.Box2I(innerBBox)
260 outerBBox.clip(self._bbox)
268 """Get dimensions of inner region of the patches (all are the same) 270 @return dimensions of inner region of the patches (as an afwGeom Extent2I) 275 """Get minimum overlap of adjacent sky tracts 277 @return minimum overlap between adjacent sky tracts, as an afwGeom Angle 282 """Get list of sky coordinates of vertices that define the boundary of the inner region 284 @warning: this is not a deep copy 285 @warning vertexCoordList will likely become a geom SphericalConvexPolygon someday. 292 @warning: this is not a deep copy 297 return "TractInfo(id=%s)" % (self.
_id,)
300 return "TractInfo(id=%s, ctrCoord=%s)" % (self.
_id, self.
_ctrCoord.getVector())
304 for y
in range(yNum):
305 for x
in range(xNum):
316 """Does this tract contain the coordinate?""" 317 icrsCoord = coord.toIcrs()
319 pixels = self.
getWcs().skyToPixel(icrsCoord)
327 """Information for a tract specified explicitly 329 A tract is placed at the explicitly defined coordinates, with the nominated 330 radius. The tracts are square (i.e., the radius is really a half-size). 333 def __init__(self, ident, patchInnerDimensions, patchBorder, ctrCoord, radius, tractOverlap, wcs):
337 super(ExplicitTractInfo, self).
__init__(ident, patchInnerDimensions, patchBorder, ctrCoord,
338 vertexList, tractOverlap, wcs)
342 def _minimumBoundingBox(self, wcs):
343 """The minimum bounding box is calculated using the nominated radius""" 344 bbox = afwGeom.Box2D()
348 pixPos = wcs.skyToPixel(coord)
def getTractOverlap(self)
def _finalOrientation(self, bbox, wcs)
def _setupPatches(self, minBBox, wcs)
def getPatchInfo(self, index)
def contains(self, coord)
def getPatchInnerDimensions(self)
def __getitem__(self, index)
def _minimumBoundingBox(self, wcs)
def findPatch(self, coord)
def findPatchList(self, coordList)
def __init__(self, ident, patchInnerDimensions, patchBorder, ctrCoord, radius, tractOverlap, wcs)
def __init__(self, id, patchInnerDimensions, patchBorder, ctrCoord, vertexCoordList, tractOverlap, wcs)