def get_tangent_point(filename):
"""Return the 'tangent point' for a file or raises an IOError.
Given an image, return the ra/dec used in the WCS transform.
For tables look for the column with a WCS transform.
This is not a general-purpose routine, since it makes
a number of assumptions.
"""
bl = cxcdm.dmBlockOpen(filename)
try:
btype = cxcdm.dmBlockGetType(bl)
if btype == cxcdm.dmIMAGE:
(ra0, dec0) = _get_tangent_point_image(filename, bl)
elif btype == cxcdm.dmTABLE:
(ra0, dec0) = _get_tangent_point_table(filename, bl)
else:
raise IOError(
"Unable to find tangent point for block " +
"{} of {}".format(cxcdm.dmBlockGetName(bl), filename))
finally:
cxcdm.dmBlockClose(bl)
v3("Tangent point in {}: {} {}".format(filename, ra0, dec0))
return (ra0, dec0)
def get_content(f):
bl = cxcdm.dmBlockOpen(f, update=False)
try:
keys = cxcdm.dmKeyRead(bl, 'CONTENT')
content = keys[1].decode('ascii')
return content
finally:
cxcdm.dmBlockClose(bl)
def put_history(self, infile ):
"""
Use the CXCDM to write history records
"""
from cxcdm import dmBlockOpen, dmBlockClose, dmBlockWriteComment, dmBlockMoveToKey, dmBlockGetNoKeys
tab = dmBlockOpen( infile, update=True)
dmBlockMoveToKey( tab, dmBlockGetNoKeys(tab))
for t,v in self.history:
dmBlockWriteComment( tab, t, v )
dmBlockClose(tab)
def get_subspace(infile, binsize):
"""Obtain the sky range of a region filtered image, using the file
subspace.
This may also be used with unfiltered images too"""
lo = {"x": None, "y": None}
hi = {"x": None, "y": None}
v4("get_subspace: infile={} binsize={}".format(infile, binsize))
bl = cxcdm.dmBlockOpen(infile)
try:
num_compt = cxcdm.dmBlockGetNoSubspaceCpts(bl)
v4("get_subspace: found {} sub-space components".format(num_compt))
if num_compt == 0:
v1("No subspace components found for " + infile)
else:
# get the union of all the sky x- and y-ranges from the subspace
for i in range(1, num_compt + 1):
v4("get_subspace: moving to subspace block #{}".format(i))
cxcdm.dmBlockSetSubspaceCpt(bl, i)
for colname in ["x", "y"]:
try:
col = cxcdm.dmSubspaceColOpen(bl, colname)
(subspace_lo,
subspace_hi) = cxcdm.dmSubspaceColGet(col)
v4("get_subspace: col={} subspace lo={} hi={}".format(
colname, subspace_lo, subspace_hi))
for (lo_sub, hi_sub) in zip(subspace_lo, subspace_hi):
if lo[colname] is None:
lo[colname] = lo_sub
else:
lo[colname] = min(lo[colname], lo_sub)
if hi[colname] is None:
hi[colname] = hi_sub
else:
hi[colname] = max(hi[colname], hi_sub)
except RuntimeError:
v4("get_subspace: skipping block as no x/y subspace columns"
)
# if zero subspace components, exit quietly, since
# cxcdm throws a RuntimeError
pass
finally:
cxcdm.dmBlockClose(bl)
return (AxisRange(lo["x"], hi["x"],
binsize), AxisRange(lo["y"], hi["y"], binsize))
def get_aimpoint(infile):
"""Return the aim-point ccd_id/chip value by
inspecting the contents of the first table block
that starts with the name 'GTI'.
Raises an IOError if unable to find a block that
starts with GTI.
"""
v3("Looking for aimpoint CCD in {}".format(infile))
try:
ds = cxcdm.dmDatasetOpen(infile)
except IOError as ioe:
msg = str(ioe)
if msg.startswith("dmDatasetOpen() "):
msg = msg[16:]
raise IOError(msg)
try:
nblocks = cxcdm.dmDatasetGetNoBlocks(ds)
v4("File has {} blocks".format(nblocks))
for blnum in range(1, nblocks + 1):
blname = cxcdm.dmDatasetGetBlockName(ds, blnum)
v4("Block #{} = {}".format(blnum, blname))
if blname.startswith("GTI") and \
cxcdm.dmDatasetGetBlockType(ds, blnum) == cxcdm.dmTABLE:
bl = cxcdm.dmDatasetGetBlock(ds, blnum)
try:
nkeys = cxcdm.dmBlockGetNoKeys(bl)
for keynum in range(1, nkeys + 1):
dd = cxcdm.dmBlockGetKey(bl, keynum)
# TODO: is it CHIP for HRC data? Does it matter?
if cxcdm.dmGetName(dd) == 'CCD_ID':
aimpoint = cxcdm.dmGetData(dd)
v4("Found aimpoint CCD = {}".format(aimpoint))
return aimpoint
finally:
cxcdm.dmBlockClose(bl)
raise IOError(
"No CCD_ID keyword found in {} block of {}".format(
blname, infile))
raise IOError("No block starting with GTI found in {}".format(infile))
finally:
cxcdm.dmDatasetClose(ds)
def get_image_units(fname):
"""Returns the units of the image, which can be an
empty string. A TypeError is raised if the input is not
an image."""
# We do not use dmImageOpen since that will promote a
# table to an image (if possible) and we do not want that.
#
bl = cxcdm.dmBlockOpen(fname)
try:
if cxcdm.dmBlockGetType(bl) != cxcdm.dmIMAGE:
raise IOError("The file {} is not an image.".format(fname))
dd = cxcdm.dmImageGetDataDescriptor(bl)
unit = cxcdm.dmGetUnit(dd)
finally:
cxcdm.dmBlockClose(bl)
return unit
def get_history(self, filename ):
"""
Use CXCDM to get history records
"""
from cxcdm import dmBlockOpen, dmBlockClose, dmBlockReadComment, dmBlockMoveToKey, dmBlockGetNoKeys
self.history = []
tab = dmBlockOpen( filename )
for ii in range( 1, dmBlockGetNoKeys(tab)+1 ):
dmBlockMoveToKey(tab,ii)
while True:
hist = dmBlockReadComment(tab)
if None == hist:
break
elif 2 != len(hist):
break
elif not any(hist):
break
else:
self.history.append(hist)
dmBlockClose(tab)