lsst.afw  v23.0.x-g89e8071bfa+60ce4897b0
skyWcs.py
Go to the documentation of this file.
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.
8 #
9 # This program is free software: you can redistribute it and/or modify
10 # it under the terms of the GNU General Public License as published by
11 # the Free Software Foundation, either version 3 of the License, or
12 # (at your option) any later version.
13 #
14 # This program is distributed in the hope that it will be useful,
15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 # GNU General Public License for more details.
18 #
19 # You should have received a copy of the GNU General Public License
20 # along with this program. If not, see <https://www.gnu.org/licenses/>.
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 from ._hpxUtils import makeHpxWcs
30 
31 __all__ = ["SkyWcs", "makeCdMatrix", "makeFlippedWcs", "makeSkyWcs",
32  "makeModifiedWcs", "makeTanSipWcs", "makeWcsPairTransform",
33  "getIntermediateWorldCoordsToSky", "getPixelToIntermediateWorldCoords",
34  "makeHpxWcs"]
35 
36 
37 @continueClass # noqa: F811 (FIXME: remove for py 3.8+)
38 class SkyWcs: # noqa: F811
39  def pixelToSkyArray(self, x, y, degrees=False):
40  """
41  Convert numpy array pixels (x, y) to numpy array sky (ra, dec)
42  positions.
43 
44  Parameters
45  ----------
46  x : `np.ndarray`
47  Array of x values.
48  y : `np.ndarray`
49  Array of y values.
50  degrees : `bool`, optional
51  Return ra, dec arrays in degrees if True.
52 
53  Returns
54  -------
55  ra : `np.ndarray`
56  Array of Right Ascension. Units are radians unless
57  degrees=True.
58  dec : `np.ndarray`
59  Array of Declination. Units are radians unless
60  degrees=True.
61  """
62  xy = np.vstack((x, y))
63  ra, dec = np.vsplit(self.getTransform().getMapping().applyForward(xy), 2)
64  ra %= (2.*np.pi)
65 
66  if degrees:
67  return np.rad2deg(ra.ravel()), np.rad2deg(dec.ravel())
68  else:
69  return ra.ravel(), dec.ravel()
70 
71  def skyToPixelArray(self, ra, dec, degrees=False):
72  """
73  Convert numpy array sky (ra, dec) positions to numpy array
74  pixels (x, y).
75 
76  Parameters
77  ----------
78  ra : `np.ndarray`
79  Array of Right Ascension. Units are radians unless
80  degrees=True.
81  dec : `np.ndarray`
82  Array of Declination. Units are radians unless
83  degrees=True.
84  degrees : `bool`, optional
85  Input ra, dec arrays are degrees if True.
86 
87  Returns
88  -------
89  x : `np.ndarray`
90  Array of x values.
91  y : `np.ndarray`
92  Array of y values.
93  """
94  radec = np.vstack((ra, dec))
95  if degrees:
96  radec = np.deg2rad(radec)
97 
98  x, y = np.vsplit(self.getTransform().getMapping().applyInverse(radec), 2)
99 
100  return x.ravel(), y.ravel()
101 
102 
103 SkyWcs.__reduce__ = reduceTransform
def skyToPixelArray(self, ra, dec, degrees=False)
Definition: skyWcs.py:71
def pixelToSkyArray(self, x, y, degrees=False)
Definition: skyWcs.py:39