lsst.skymap  13.0-5-g2a40766+22
 All Classes Namespaces Files Functions Variables Pages
utils.py
Go to the documentation of this file.
1 #
2 # LSST Data Management System
3 # Copyright 2008, 2009, 2010 LSST Corporation.
4 #
5 # This product includes software developed by the
6 # LSST Project (http://www.lsst.org/).
7 #
8 # This program is free software: you can redistribute it and/or modify
9 # it under the terms of the GNU General Public License as published by
10 # the Free Software Foundation, either version 3 of the License, or
11 # (at your option) any later version.
12 #
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
17 #
18 # You should have received a copy of the LSST License Statement and
19 # the GNU General Public License along with this program. If not,
20 # see <http://www.lsstcorp.org/LegalNotices/>.
21 #
22 import numpy
23 
24 import lsst.afw.coord as afwCoord
25 import lsst.afw.geom as afwGeom
26 
27 __all__ = ["coordFromVec"]
28 
29 _TinyFloat = numpy.finfo(float).tiny
30 
31 
32 def coordFromVec(vec, defRA=None):
33  """Convert an ICRS cartesian vector to an ICRS Coord
34 
35  @param[in] vec: an ICRS catesian vector as a sequence of three floats
36  @param[in] defRA: the RA to use if the vector is too near a pole (an afwGeom Angle);
37  ignored if not near a pole
38 
39  @throw RuntimeError if vec too near a pole and defRA is None
40  """
41  if abs(vec[0]) < _TinyFloat and abs(vec[1]) < _TinyFloat:
42  if defRA is None:
43  raise RuntimeError("At pole and defRA==None")
44  if vec[2] > 0:
45  dec = 90.0
46  else:
47  dec = -90.0
48  return afwCoord.makeCoord(afwCoord.ICRS, defRA, afwGeom.Angle(dec, afwGeom.degrees))
49  return afwCoord.makeCoord(afwCoord.ICRS, afwGeom.Point3D(*vec))