def _copyMissingCards(newHdr, oldHdr): """helps makeHeaderFromTemplate. Specifically, it copies over all cards from oldHder to newHdr not yet present there. It will also move over history and comment cards. This will modify newHdr in place. """ commentCs, historyCs = [], [] for card in oldHdr.ascardlist(): if card.key=="COMMENT": commentCs.append(card) elif card.key=="HISTORY": if not "GAVO DaCHS template used" in card.value: historyCs.append(card) elif card.key: if card.key not in newHdr: newHdr.append(card, end=True) for card in historyCs: newHdr.append(card, end=True) newHdr.append(pyfits.Card(value=""), end=True) for card in commentCs: newHdr.append(card, end=True)
def _applyTemplate(hdr, template, values):
"""helps makeHeaderFromTemplate.
Specifically, it moves items in values mentioned in template into
header in template's order. hdr and values are modified in that process.
"""
for tp in template:
if isinstance(tp, pyfits.Card):
tp.value = values.pop(tp.key, tp.value)
hdr.append(tp, end=True)
else:
key, comment = tp
argKey = key.replace("-", "_")
if values.get(argKey) is not None:
try:
val = values[argKey]
if isinstance(val, unicode):
val = val.encode("ascii")
hdr.append(pyfits.Card(key, val, comment), end=True)
except Exception, ex:
if hasattr(ex, "args") and isinstance(ex.args[0], basestring):
ex.args = ("While constructing card %s: %s"%(
key, ex.args[0]),)+ex.args[1:]
raise
values.pop(argKey, None)
def copyFields(header, cardList,
ignoredHeaders=frozenset(DEFAULT_IGNORED_HEADERS)):
"""copies over all cards from cardList into header, excluding headers
named in ignoredHeaders.
ignoredHeaders must be all lowercase.
"""
for card in cardList:
if card.key=="COMMENT":
header.add_comment(card.value)
elif card.key=="HISTORY":
header.add_history(card.value)
elif card.key=="":
header.append(pyfits.Card("", card.value), end=True)
elif card.key.lower() in ignoredHeaders:
pass
else:
header.update(card.key, card.value, card.comment)
def makeHeaderFromTemplate(template, originalHeader=None, **values):
"""returns a new pyfits.Header from template with values filled in.
template usually is the name of a template previously registered with
registerTemplate, or one of DaCHS predefined template names (currently,
minimal and wfpdb). In a pinch, you can also pass in an immediate
headers.
originalHeader can be a pre-existing header; the history and comment
cards are copied over from it, and if any of its other cards have not
yet been added to the header, they will be added in the order that they
apprear there.
values for which no template item is given are added in random order
after the template unless an originalHeader is passed. In that case,
they are assumed to originate there and are ignored.
"""
values = values.copy()
hdr = pyfits.Header()
if isinstance(template, basestring):
templateName = template
template = getTemplateForName(templateName)
else:
try:
templateName = getNameForTemplate(template)
except base.NotFoundError:
base.notifyWarning("Using anonymous FITS template.")
templateName = "anonymous"
_applyTemplate(hdr, template, values)
if originalHeader:
_copyMissingCards(hdr, originalHeader)
elif values:
base.ui.notifyWarning("The following values were left after"
" applying a FITS template and will be added in random order: %s"%
(", ").join(values.keys()))
for key, value in values.iteritems():
hdr.append(pyfits.Card(key, value), end=True)
hdr.add_history("GAVO DaCHS template used: "+templateName)
return hdr
def _makeHeaderSequence(keyTpl, commentTpl):
try:
return [
(keyTpl%ind, commentTpl%numeral)
for ind, numeral in [
(1, "1st"),
(2, "2nd"),
(3, "3rd"),]]
except TypeError:
raise base.ReportableError("Invalid header sequence templates: %r %r"%(
keyTpl, commentTpl))
# FITS header template for a minimal pixel array
MINIMAL_IMAGE_TEMPLATE = [
pyfits.Card("SIMPLE", True),
pyfits.Card("EXTEND", True),
("BITPIX", "Array data type"),
pyfits.Card("NAXIS", 2),
("NAXIS1", "Number of elements along 1st axis"),
("NAXIS2", "Number of elements along 2nd axis"),
("BZERO", "Zero point of pixel scaling function"),
("BSCALE", "Slope of pixel scaling function"),]
WCS_TEMPLATE = [
pyfits.Card(value="-------------------- Spatial WCS"),
('EQUNIOX', "Equinox of RA and Dec"),
('WCSAXES', "Number of FITS axes covered by WCS"),
('CTYPE1', "Projection on axis 1"),
('CTYPE2', "Projection on axis 2"),