1 from __future__
import division
2 from builtins
import range
3 from builtins
import object
27 from .patchInfo
import PatchInfo
29 __all__ = [
"TractInfo"]
33 """Information about a tract in a SkyMap sky pixelization 35 The tract is subdivided into rectangular patches. Each patch has the following properties: 36 - An inner region defined by an inner bounding. The inner regions of the patches exactly tile the tract, 37 and all inner regions have the same dimensions. The tract is made larger as required to make this work. 38 - An outer region defined by an outer bounding box. The outer region extends beyond the inner region 39 by patchBorder pixels in all directions, except there is no border at the edges of the tract. 40 Thus patches overlap each other but never extend off the tract. If you do not want any overlap 41 between adjacent patches then set patchBorder to 0. 42 - An index that consists of a pair of integers: 43 0 <= x index < numPatches[0] 44 0 <= y index < numPatches[1] 45 Patch 0,0 is at the minimum corner of the tract bounding box. 48 def __init__(self, id, patchInnerDimensions, patchBorder, ctrCoord, vertexCoordList, tractOverlap, wcs):
49 """Construct a TractInfo 51 @param[in] id: tract ID 52 @param[in] patchInnerDimensions: dimensions of inner region of patches (x,y pixels) 53 @param[in] patchBorder: overlap between adjacent patches (in pixels, one int) 54 @param[in] ctrCoord: ICRS sky coordinate of center of inner region of tract 55 as an lsst.afw.geom.SpherePoint; also used as the CRVAL for the WCS. 56 @param[in] vertexCoordList: list of ICRS sky coordinates (lsst.afw.geom.SpherePoint) 57 of vertices that define the boundaries of the inner region 58 @param[in] tractOverlap: minimum overlap between adjacent sky tracts; an afwGeom.Angle; 59 this defines the minimum distance the tract extends beyond the inner region in all directions 60 @param[in,out] wcs: an afwImage.Wcs; the reference pixel will be shifted as required 61 so that the lower left-hand pixel (index 0,0) has pixel position 0.0, 0.0 64 - It is not enforced that ctrCoord is the center of vertexCoordList, but SkyMap relies on it 65 - vertexCoordList will likely become a geom SphericalConvexPolygon someday. 69 assert len(patchInnerDimensions) == 2
72 raise TypeError(
"patchInnerDimensions=%s; must be two ints" % (patchInnerDimensions,))
82 def _minimumBoundingBox(self, wcs):
83 """Calculate the minimum bounding box for the tract, given the WCS 85 The bounding box is created in the frame of the supplied WCS, 86 so that it's OK if the coordinates are negative. 88 We compute the bounding box that holds all the vertices and the 91 minBBoxD = afwGeom.Box2D()
95 minBBoxD.include(wcs.skyToPixel(vertexCoord))
98 angleIncr = afwGeom.Angle(360.0, afwGeom.degrees) / float(numAngles)
99 for i
in range(numAngles):
100 offAngle = angleIncr * i
101 offCoord = vertexCoord.offset(offAngle, halfOverlap)
102 pixPos = wcs.skyToPixel(offCoord)
103 minBBoxD.include(pixPos)
106 def _setupPatches(self, minBBox, wcs):
107 """Setup for patches of a particular size. 109 We grow the bounding box to hold an exact multiple of 110 the desired size (patchInnerDimensions), while keeping 111 the center roughly the same. We return the final 112 bounding box, and the number of patches in each dimension 115 @param minBBox Minimum bounding box for tract 116 @param wcs Wcs object 117 @return final bounding box, number of patches 119 bbox = afwGeom.Box2I(minBBox)
120 bboxMin = bbox.getMin()
121 bboxDim = bbox.getDimensions()
122 numPatches = afwGeom.Extent2I(0, 0)
124 num = (bboxDim[i] + innerDim - 1) // innerDim
125 deltaDim = (innerDim * num) - bboxDim[i]
127 bboxDim[i] = innerDim * num
128 bboxMin[i] -= deltaDim // 2
130 bbox = afwGeom.Box2I(bboxMin, bboxDim)
131 return bbox, numPatches
133 def _finalOrientation(self, bbox, wcs):
134 """Determine the final orientation 136 We offset everything so the lower-left corner is at 0,0 137 and compute the final Wcs. 139 @param bbox Current bounding box 140 @param wcs Current Wcs 141 @return revised bounding box, revised Wcs 143 finalBBox = afwGeom.Box2I(afwGeom.Point2I(0, 0), bbox.getDimensions())
146 pixPosOffset = afwGeom.Extent2D(finalBBox.getMinX() - bbox.getMinX(),
147 finalBBox.getMinY() - bbox.getMinY())
148 wcs = wcs.copyAtShiftedPixelOrigin(pixPosOffset)
149 return finalBBox, wcs
152 """Find the patch containing the specified coord 154 @param[in] coord: ICRS sky coordinate (lsst.afw.geom.SpherePoint) 155 @return PatchInfo of patch whose inner bbox contains the specified coord 157 @raise LookupError if coord is not in tract or we cannot determine the 158 pixel coordinate (which likely means the coord is off the tract). 160 @note This routine will be more efficient if coord is ICRS. 163 pixel = self.
getWcs().skyToPixel(coord)
166 raise LookupError(
"Unable to determine pixel position for coordinate %s" % (coord,))
167 pixelInd = afwGeom.Point2I(pixel)
169 raise LookupError(
"coord %s is not in tract %s" % (coord, self.
getId()))
174 """Find patches containing the specified list of coords 176 @param[in] coordList: list of sky coordinates (lsst.afw.geom.SpherePoint) 177 @return list of PatchInfo for patches that contain, or may contain, the specified region. 178 The list will be empty if there is no overlap. 181 * This may give incorrect answers on regions that are larger than a tract 182 * This uses a naive algorithm that may find some patches that do not overlap the region 183 (especially if the region is not a rectangle aligned along patch x,y). 185 box2D = afwGeom.Box2D()
186 for coord
in coordList:
188 pixelPos = self.
getWcs().skyToPixel(coord)
192 box2D.include(pixelPos)
193 bbox = afwGeom.Box2I(box2D)
202 for xInd
in range(llPatchInd[0], urPatchInd[0]+1)
203 for yInd
in range(llPatchInd[1], urPatchInd[1]+1))
206 """Get bounding box of tract (as an afwGeom.Box2I) 208 return afwGeom.Box2I(self._bbox)
211 """Get ICRS sky coordinate of center of tract (as an lsst.afw.geom.SpherePoint) 221 """Get the number of patches in x, y 223 @return the number of patches in x, y 230 @return patch border (pixels) 235 """Return information for the specified patch 237 @param[in] index: index of patch, as a pair of ints 238 @return patch info, an instance of PatchInfo 240 @raise IndexError if index is out of range 244 raise IndexError(
"Patch index %s is not in range [0-%d, 0-%d]" %
248 if not self._bbox.
contains(innerBBox):
250 "Bug: patch index %s valid but inner bbox=%s not contained in tract bbox=%s" %
251 (index, innerBBox, self._bbox))
252 outerBBox = afwGeom.Box2I(innerBBox)
254 outerBBox.clip(self._bbox)
262 """Get dimensions of inner region of the patches (all are the same) 264 @return dimensions of inner region of the patches (as an afwGeom Extent2I) 269 """Get minimum overlap of adjacent sky tracts 271 @return minimum overlap between adjacent sky tracts, as an afwGeom Angle 276 """Get list of sky coordinates of vertices that define the boundary of the inner region 278 @warning: this is not a deep copy 279 @warning vertexCoordList will likely become a geom SphericalConvexPolygon someday. 286 @warning: this is not a deep copy 291 return "TractInfo(id=%s)" % (self.
_id,)
294 return "TractInfo(id=%s, ctrCoord=%s)" % (self.
_id, self.
_ctrCoord.getVector())
298 for y
in range(yNum):
299 for x
in range(xNum):
310 """Does this tract contain the coordinate?""" 312 pixels = self.
getWcs().skyToPixel(coord)
320 """Information for a tract specified explicitly 322 A tract is placed at the explicitly defined coordinates, with the nominated 323 radius. The tracts are square (i.e., the radius is really a half-size). 326 def __init__(self, ident, patchInnerDimensions, patchBorder, ctrCoord, radius, tractOverlap, wcs):
330 super(ExplicitTractInfo, self).
__init__(ident, patchInnerDimensions, patchBorder, ctrCoord,
331 vertexList, tractOverlap, wcs)
333 bboxD = afwGeom.BoxD(self.
getBBox())
338 def _minimumBoundingBox(self, wcs):
339 """The minimum bounding box is calculated using the nominated radius""" 340 bbox = afwGeom.Box2D()
343 pixPos = wcs.skyToPixel(cornerCoord)
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)