""" skytopix - A module to perform coordinate transformation from sky
to pixel coordinates.
:Authors: Warren Hack
:License: :doc:`/LICENSE`
"""
import numpy as np
from . import util,tweakutils
from stwcs import wcsutil
from . import __version__
__taskname__ = 'skytopix'
__all__ = ['rd2xy']
blank_list = [None, '', ' ']
[docs]
def rd2xy(input, ra=None, dec=None, coordfile=None, colnames=None,
precision=6, output=None, verbose=True):
"""Primary interface to perform coordinate transformations from
pixel to sky coordinates using STWCS and full distortion models
read from the input image header. Input positions must be in the
form of RA/Dec strings or as columns in a coordinate file.
Parameters
----------
input : str
Full filename with path of input image, an extension name
['sci',1] should be provided if input is a multi-extension
FITS file
ra : string or list or array, optional
RA from input image for a single or multiple positions
(with or without ``':'``)
like ``'19:10:50.337406303'`` or ``'19 10 50.337406303'``
dec : string or list or array, optional
Dec from input image for a single or multiple positions
(with or without ``':'``)
like ``'-60:2:22.186557409'`` or ``'-60 2 22.186557409'``
coordfile : str, optional
Full filename with path of file with sky coordinates
colnames : str, optional
Comma separated list of column names or list of column name strings
from 'coordfile' files containing sky coordinates, respectively.
This parameter will default to first two columns if None are specified.
Column names for ASCII files will use 'c1','c2',... convention.
Valid syntax: ['c1','c3'] or 'c1,c3'
separator : str, optional
Non-blank separator used as the column delimiter in the coords file
precision : int, optional
Number of floating-point digits in output values
output : str, optional
Name of output file with results, if desired
verbose : bool
Print out full list of transformation results (default: False)
Returns
-------
x : float or array
X position of pixel. If more than 1 input value, then it will be a
numpy array.
y : float or array
Y position of pixel. If more than 1 input value, then it will be a
numpy array.
Notes
-----
This module performs a full distortion-corrected coordinate
transformation based on all WCS keywords and any recognized
distortion keywords from the input image header.
Examples
--------
1. The following command will transform the position 00:22:36.79 -72:4:9.0 into a
position on the image 'input_flt.fits[sci,1]' using::
>>> from drizzlepac import skytopix
>>> x,y = skytopix.rd2xy("input_file_flt.fits[sci,1]", "00:22:36.79", "-72:4:9.0")
2. The set of sky positions from 'input_flt.fits[sci,1]' stored as
the 3rd and 4th columns from the ASCII file 'radec_sci1.dat'
will be transformed and written out to 'xy_sci1.dat' using::
>>> from drizzlepac import skytopix
>>> x,y = skytopix.rd2xy("input_flt.fits[sci,1]", coordfile='radec_sci1.dat',
... colnames=['c3','c4'], output="xy_sci1.dat")
"""
single_coord = False
if coordfile is not None:
if colnames in blank_list:
colnames = ['c1','c2']
elif isinstance(colnames,type('a')):
colnames = colnames.split(',')
# convert input file coordinates to lists of decimal degrees values
xlist,ylist = tweakutils.readcols(coordfile,cols=colnames)
else:
if isinstance(ra,np.ndarray):
ralist = ra.tolist()
declist = dec.tolist()
elif not isinstance(ra, list):
ralist = [ra]
declist = [dec]
else:
ralist = ra
declist = dec
xlist = [0]*len(ralist)
ylist = [0]*len(ralist)
if len(xlist) == 1:
single_coord = True
for i,(r,d) in enumerate(zip(ralist,declist)):
# convert input value into decimal degrees value
xval,yval = tweakutils.parse_skypos(r,d)
xlist[i] = xval
ylist[i] = yval
# start by reading in WCS+distortion info for input image
inwcs = wcsutil.HSTWCS(input)
if inwcs.wcs.is_unity():
print("####\nNo valid WCS found in {}.\n Results may be invalid.\n####\n".format(input))
# Now, convert pixel coordinates into sky coordinates
try:
outx,outy = inwcs.all_world2pix(xlist,ylist,1)
except RuntimeError:
outx,outy = inwcs.wcs_world2pix(xlist,ylist,1)
# add formatting based on precision here...
xstr = []
ystr = []
fmt = "%."+repr(precision)+"f"
for x,y in zip(outx,outy):
xstr.append(fmt%x)
ystr.append(fmt%y)
if verbose or (not verbose and util.is_blank(output)):
print ('# Coordinate transformations for ',input)
print('# X Y RA Dec\n')
for x,y,r,d in zip(xstr,ystr,xlist,ylist):
print("%s %s %s %s"%(x,y,r,d))
# Create output file, if specified
if output:
f = open(output,mode='w')
f.write("# Coordinates converted from %s\n"%input)
for x,y in zip(xstr,ystr):
f.write('%s %s\n'%(x,y))
f.close()
print('Wrote out results to: ',output)
if single_coord:
outx = outx[0]
outy = outy[0]
return outx, outy
#--------------------------------
# TEAL Interface functions
# (these functions are deprecated)
#---------------------------------
def run(configObj):
coordfile = util.check_blank(configObj['coordfile'])
colnames = util.check_blank(configObj['colnames'])
outfile = util.check_blank(configObj['output'])
rd2xy(configObj['input'],
ra = configObj['ra'], dec = configObj['dec'],
coordfile = coordfile, colnames = colnames,
precision= configObj['precision'],
output= outfile, verbose = configObj['verbose'])