def cutout_range(self,
rac,
decc,
xw,
yw,
units='pixels',
coordsys='galactic'):
"""
computes the pixel range (min max) of a frame centered at (rac, decc) with width xw, yw (in arc seconds)
:param rac:
:param decc:
:param xw:
:param yw:
:return:
"""
head = self.header
wcs = pywcs.WCS(head)
if units == 'wcs':
if coordsys == 'celestial' and wcs.wcs.lngtyp == 'GLON':
rac, decc = coords.Position((rac, decc),
system=coordsys).galactic()
elif coordsys == 'galactic' and wcs.wcs.lngtyp == 'RA':
rac, decc = coords.Position((rac, decc),
system=coordsys).j2000()
else:
raise ValueError("problem with wcs instance.")
xx, yy = wcs.all_world2pix(rac, decc, 0)
xx = int(xx)
yy = int(yy)
print('the center of the image is at pixel coordinates %f, %f.' %
(xx, yy))
if units == 'pixels':
xmin, xmax = np.max([0, xx - xw]), np.min([self.naxis1, xx + xw])
ymin, ymax = np.max([0, yy - yw]), np.min([self.naxis2, yy + yw])
elif units == 'arcseconds':
cd1, cd2 = self.pixel_size
xmin, xmax = np.max([0, xx - xw / np.abs(cd1)]), np.min(
[self.naxis1, xx + xw / np.abs(cd1)])
ymin, ymax = np.max([0, yy - yw / np.abs(cd2)]), np.min(
[self.naxis2, yy + yw / np.abs(cd2)])
else:
raise Exception("Can't use units %s." % units)
if xmax < 0 or ymax < 0:
raise ValueError("Max Coordinate is outside of map: %f,%f." %
(xmax, ymax))
if ymin >= head.get('NAXIS2') or xmin >= head.get('NAXIS1'):
raise ValueError("Min Coordinate is outside of map: %f,%f." %
(xmin, ymin))
return xmin, xmax, ymin, ymax
def coords_in_image(fitsfile, lon, lat, system='galactic'):
"""
Determine whether the coordinates are inside the image
"""
if not isinstance(fitsfile, fits.HDUList):
fitsfile = fits.open(fitsfile)
wcs = pywcs.WCS(flatten_header(fitsfile[0].header))
if 'RA' in wcs.wcs.ctype[0]:
pos = coordinates.Position((lon, lat), system=system)
lon, lat = pos.j2000()
if 'GLON' in wcs.wcs.ctype[0]:
pos = coordinates.Position((lon, lat), system=system)
lon, lat = pos.galactic()
x, y = wcs.wcs_world2pix(lon, lat, 0)
#DEBUG print x,y,wcs.naxis1,wcs.naxis2
if (0 < x < wcs.naxis1) and (0 < y < wcs.naxis2):
return True
else:
return False
def _cutout(self,
fits_filename,
xc,
yc,
xw,
yw,
units='pixels',
clobber=True,
useMontage=False,
coordsys='galactic',
verbose=False,
exposure_map=False):
"""
Inputs:
file - pyfits HDUList (must be 2D)
xc,yc - x and y coordinates in the fits files' coordinate system (CTYPE)
xw,yw - x and y width (pixels or wcs)
units - specify units to use: either pixels or wcs
outfile - optional output file
"""
# file = pyfits.open(fits_filename)
# head = file['SCI'].header.copy()
head = self.header.copy()
wcs = pywcs.WCS(head)
if units == 'wcs':
if coordsys == 'celestial' and wcs.wcs.lngtyp == 'GLON':
xc, yc = coords.Position((xc, yc), system=coordsys).galactic()
elif coordsys == 'galactic' and wcs.wcs.lngtyp == 'RA':
xc, yc = coords.Position((xc, yc), system=coordsys).j2000()
xx, yy = wcs.all_world2pix(xc, yc, 0)
print('the center of the image is at pixel coordinates %f, %f.' %
(xx, yy))
if units == 'pixels':
xmin, xmax = np.max([0, xx - xw]), np.min([self.naxis1, xx + xw])
ymin, ymax = np.max([0, yy - yw]), np.min([self.naxis2, yy + yw])
elif units == 'wcs':
xmin, xmax = np.max([0, xx - xw / np.abs(self.cd1)]), np.min(
[self.naxis1, xx + xw / np.abs(self.cd1)])
ymin, ymax = np.max([0, yy - yw / np.abs(self.cd2)]), np.min(
[self.naxis2, yy + yw / np.abs(self.cd2)])
else:
raise Exception("Can't use units %s." % units)
self._xmin_c, self._xmax_c = xmin, xmax
self._ymin_c, self._ymax_c = ymin, ymax
if xmax < 0 or ymax < 0:
raise ValueError("Max Coordinate is outside of map: %f,%f." %
(xmax, ymax))
if ymin >= head.get('NAXIS2') or xmin >= head.get('NAXIS1'):
raise ValueError("Min Coordinate is outside of map: %f,%f." %
(xmin, ymin))
head = self.change_header(head, xmin, xmax, ymin, ymax)
img = self.image_full()[int(ymin):int(ymax),
int(xmin):int(xmax)].copy()
# img = file['SCI'].data[ymin:ymax, xmin:xmax]
if verbose:
print("Cut image %s to %s. xrange: %f:%f, yrange: %f:%f" %
(fits_filename, img.shape, xmin, xmax, ymin, ymax))
if exposure_map:
exp_map = self.exposure_full()[int(ymin):int(ymax),
int(xmin):int(xmax)].copy()
else:
exp_map = None
ra_coord, dec_coord = self.get_coordinates(xmin, xmax, ymin, ymax, wcs)
return img, head, exp_map, ra_coord, dec_coord
def rotcrop_cube(x1,
y1,
x2,
y2,
cubename,
outname,
xwidth=25,
ywidth=25,
in_system='galactic',
out_system='equatorial',
overwrite=True,
newheader=None,
xcen=None,
ycen=None):
"""
Crop a data cube and then rotate it with montage
"""
cubefile = fits.open(cubename)
if xcen is None and ycen is None:
pos1 = coordinates.Position([x1, y1], system=in_system)
pos2 = coordinates.Position([x2, y2], system=in_system)
if cubefile[0].header.get('CTYPE1')[:2] == 'RA':
x1, y1 = pos1.j2000()
x2, y2 = pos2.j2000()
coord_system = 'celestial'
elif cubefile[0].header.get('CTYPE1')[:4] == 'GLON':
x1, y1 = pos1.galactic()
x2, y2 = pos2.galactic()
coord_system = 'galactic'
xcen = (x1 + x2) / 2.0
ycen = (y1 + y2) / 2.0
print(xcen, ycen, xwidth, ywidth, coord_system)
else:
coord_system = in_system
sc = subcube(cubefile[0].data,
xcen,
xwidth,
ycen,
ywidth,
widthunits='pixels',
units="wcs",
header=cubefile[0].header,
return_HDU=True)
# note: there should be no security risk here because fits' writeto
# will not overwrite by default
tempcube = tempfile.mktemp(suffix='.fits')
sc.writeto(tempcube)
pa = posang.posang(x1, y1, x2, y2, system=coord_system) - 90
if newheader is None:
newheader = sc.header.copy()
cd11 = newheader.get('CDELT1') if newheader.get(
'CDELT1') else newheader.get('CD1_1')
cd22 = newheader.get('CDELT2') if newheader.get(
'CDELT2') else newheader.get('CD2_2')
cd12 = newheader.get('CD1_2') if newheader.get('CD1_2') else 0.0
cd21 = newheader.get('CD2_1') if newheader.get('CD2_1') else 0.0
cdelt = numpy.sqrt(cd11**2 + cd12**2)
tempheader = tempfile.mktemp(suffix='.hdr')
ycensign = "+" if numpy.sign(ycen) >= 0 else "-"
montage.mHdr("%s %1s%s" % (xcen, ycensign, numpy.abs(ycen)),
xwidth * cdelt,
tempheader,
system=out_system,
height=ywidth * cdelt,
pix_size=cdelt * 3600.0,
rotation=pa)
os.system("sed -i bck '/END/d' %s" % (tempheader))
newheader2 = fits.Header()
newheader2.fromTxtFile(tempheader)
#newheader2.fromtextfile(tempheader)
for key in ('CRPIX3', 'CRVAL3', 'CDELT3', 'CD3_3', 'CUNIT3',
'WCSTYPE3', 'CTYPE3'):
if newheader.get(key):
newheader2[key] = newheader.get(key)
if newheader.get('CD3_3') and newheader2.get('CDELT3') is None:
newheader2['CDELT3'] = newheader.get('CD3_3')
if astropy.version.major >= 2 or (astropy.version.major == 1
and astropy.version.minor >= 3):
newheader2.toTxtFile(tempheader, overwrite=True)
else:
newheader2.toTxtFile(tempheader, clobber=True)
#if newheader2.get('CDELT3') is None:
# raise Exception("No CD3_3 or CDELT3 in header.")
else:
if isinstance(newheader, str):
newheader2 = fits.Header()
newheader2.fromTxtFile(newheader)
tempheader = tempfile.mktemp(suffix='.hdr')
if astropy.version.major >= 2 or (astropy.version.major == 1
and astropy.version.minor >= 3):
newheader2.toTxtFile(tempheader, overwrite=True)
else:
newheader2.toTxtFile(tempheader, clobber=True)
montage.wrappers.reproject_cube(tempcube,
outname,
header=tempheader,
clobber=overwrite)
#print "\n",outname
#os.system('imhead %s | grep CDELT' % outname)
# AWFUL hack because montage removes CDELT3
tempcube = fits.open(outname)
tempcube.header = newheader2
#if tempcube.header.get('CDELT3') is None:
# raise Exception("No CD3_3 or CDELT3 in header.")
#print tempcube.header.get('CDELT3')
if astropy.version.major >= 2 or (astropy.version.major == 1
and astropy.version.minor >= 3):
tempcube.writeto(outname, overwrite=True)
else:
tempcube.writeto(outname, clobber=True)
#print tempcube.get('CDELT3')
#print "\n",outname
#os.system('imhead %s | grep CDELT' % outname)
return
