lsst.afw  21.0.0-18-g1421380c6+e734d31160
skyWcs.py
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1 # This file is part of afw.
2 #
3 # Developed for the LSST Data Management System.
4 # This product includes software developed by the LSST Project
5 # (https://www.lsst.org).
6 # See the COPYRIGHT file at the top-level directory of this distribution
7 # for details of code ownership.
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21 
22 import numpy as np
23 
24 from lsst.utils import continueClass
25 from ._python import reduceTransform
26 from ._geom import (SkyWcs, makeCdMatrix, makeFlippedWcs, makeModifiedWcs,
27  makeSkyWcs, makeTanSipWcs, makeWcsPairTransform,
28  getIntermediateWorldCoordsToSky, getPixelToIntermediateWorldCoords)
29 
30 __all__ = ["SkyWcs", "makeCdMatrix", "makeFlippedWcs", "makeSkyWcs",
31  "makeModifiedWcs", "makeTanSipWcs", "makeWcsPairTransform",
32  "getIntermediateWorldCoordsToSky", "getPixelToIntermediateWorldCoords"]
33 
34 
35 @continueClass # noqa: F811 (FIXME: remove for py 3.8+)
36 class SkyWcs: # noqa: F811
37  def pixelToSkyArray(self, x, y, degrees=False):
38  """
39  Convert numpy array pixels (x, y) to numpy array sky (ra, dec)
40  positions.
41 
42  Parameters
43  ----------
44  x : `np.ndarray`
45  Array of x values.
46  y : `np.ndarray`
47  Array of y values.
48  degrees : `bool`, optional
49  Return ra, dec arrays in degrees if True.
50 
51  Returns
52  -------
53  ra : `np.ndarray`
54  Array of Right Ascension. Units are radians unless
55  degrees=True.
56  dec : `np.ndarray`
57  Array of Declination. Units are radians unless
58  degrees=True.
59  """
60  xy = np.vstack((x, y))
61  ra, dec = np.vsplit(self.getTransform().getMapping().applyForward(xy), 2)
62  ra %= (2.*np.pi)
63 
64  if degrees:
65  return np.rad2deg(ra.ravel()), np.rad2deg(dec.ravel())
66  else:
67  return ra.ravel(), dec.ravel()
68 
69  def skyToPixelArray(self, ra, dec, degrees=False):
70  """
71  Convert numpy array sky (ra, dec) positions to numpy array
72  pixels (x, y).
73 
74  Parameters
75  ----------
76  ra : `np.ndarray`
77  Array of Right Ascension. Units are radians unless
78  degrees=True.
79  dec : `np.ndarray`
80  Array of Declination. Units are radians unless
81  degrees=True.
82  degrees : `bool`, optional
83  Input ra, dec arrays are degrees if True.
84 
85  Returns
86  -------
87  x : `np.ndarray`
88  Array of x values.
89  y : `np.ndarray`
90  Array of y values.
91  """
92  radec = np.vstack((ra, dec))
93  if degrees:
94  radec = np.deg2rad(radec)
95 
96  x, y = np.vsplit(self.getTransform().getMapping().applyInverse(radec), 2)
97 
98  return x.ravel(), y.ravel()
99 
100 
101 SkyWcs.__reduce__ = reduceTransform
def skyToPixelArray(self, ra, dec, degrees=False)
Definition: skyWcs.py:69
def pixelToSkyArray(self, x, y, degrees=False)
Definition: skyWcs.py:37