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Use astro_metadata_translator for all header translations and unit ex…
…traction Many methods no longer abstract because astro_metadata_translator is handling the conversions. VisitInfo is now derived directly from an ObservationInfo. Leave the existing VisitInfo classes to allow for staged migration of obs packages to the new approach.
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| Original file line number | Diff line number | Diff line change |
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| # This file is part of obs_base. | ||
| # | ||
| # Developed for the LSST Data Management System. | ||
| # This product includes software developed by the LSST Project | ||
| # (http://www.lsst.org). | ||
| # See the COPYRIGHT file at the top-level directory of this distribution | ||
| # for details of code ownership. | ||
| # | ||
| # This program is free software: you can redistribute it and/or modify | ||
| # it under the terms of the GNU General Public License as published by | ||
| # the Free Software Foundation, either version 3 of the License, or | ||
| # (at your option) any later version. | ||
| # | ||
| # This program is distributed in the hope that it will be useful, | ||
| # but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| # GNU General Public License for more details. | ||
| # | ||
| # You should have received a copy of the GNU General Public License | ||
| # along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
| # | ||
|
|
||
| import astropy.units | ||
| from astropy.utils import iers | ||
|
|
||
| # This is an unofficial ERFA interface provided by Astropy. | ||
| # We need to use this to calculate the Earth rotation angle. | ||
| # If Astropy change their ERFA support we will need to either bring the | ||
| # calculation into this package or use another python ERFA binding. | ||
| import astropy._erfa as erfa | ||
|
|
||
| from astro_metadata_translator import ObservationInfo | ||
|
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| from lsst.log import Log | ||
| from lsst.daf.base import DateTime | ||
| from lsst.geom import degrees, radians | ||
| from lsst.afw.image import VisitInfo, RotType | ||
| from lsst.afw.coord import Observatory, Weather | ||
| from lsst.geom import SpherePoint | ||
|
|
||
| __all__ = ["MakeRawVisitInfoViaObsInfo"] | ||
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| class MakeRawVisitInfoViaObsInfo(object): | ||
| """Base class functor to make a VisitInfo from the FITS header of a | ||
| raw image using `~astro_metadata_translator.ObservationInfo` translators. | ||
| Subclasses can be used if a specific | ||
| `~astro_metadata_translator.MetadataTranslator` translator should be used. | ||
| The design philosophy is to make a best effort and log warnings of | ||
| problems, rather than raising exceptions, in order to extract as much | ||
| VisitInfo information as possible from a messy FITS header without the | ||
| user needing to add a lot of error handling. | ||
| Parameters | ||
| ---------- | ||
| log : `lsst.log.Log` or None | ||
| Logger to use for messages. | ||
| (None to use ``Log.getLogger("MakeRawVisitInfoViaObsInfo")``). | ||
| """ | ||
|
|
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| metadataTranslator = None | ||
| """Header translator to use to construct VisitInfo, defaulting to | ||
| automatic determination.""" | ||
|
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| def __init__(self, log=None): | ||
| if log is None: | ||
| log = Log.getLogger("MakeRawVisitInfoViaObsInfo") | ||
| self.log = log | ||
|
|
||
| def __call__(self, md, exposureId=None): | ||
| """Construct a VisitInfo and strip associated data from the metadata. | ||
| Parameters | ||
| ---------- | ||
| md : `lsst.daf.base.PropertyList` or `lsst.daf.base.PropertySet` | ||
| Metadata to pull from. | ||
| Items that are used are stripped from the metadata. | ||
| exposureId : `int`, optional | ||
| Ignored. Here for compatibility with `MakeRawVisitInfo`. | ||
| Returns | ||
| ------- | ||
| visitInfo : `lsst.afw.image.VisitInfo` | ||
| `~lsst.afw.image.VisitInfo` derived from the header using | ||
| a `~astro_metadata_translator.MetadataTranslator`. | ||
| """ | ||
| argDict = dict() | ||
|
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| obsInfo = ObservationInfo(md, translator_class=self.metadataTranslator) | ||
|
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| # Strip all the cards out that were used | ||
| for c in obsInfo.cards_used: | ||
| del md[c] | ||
|
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| # Map the translated information into a form suitable for VisitInfo | ||
| if obsInfo.exposure_time is not None: | ||
| argDict["exposureTime"] = obsInfo.exposure_time.to_value("s") | ||
| if obsInfo.dark_time is not None: | ||
| argDict["darkTime"] = obsInfo.dark_time.to_value("s") | ||
| argDict["exposureId"] = obsInfo.detector_exposure_id | ||
|
|
||
| # VisitInfo uses the middle of the observation for the date | ||
| if obsInfo.datetime_begin is not None and obsInfo.datetime_end is not None: | ||
| tdelta = obsInfo.datetime_end - obsInfo.datetime_begin | ||
| middle = obsInfo.datetime_begin + 0.5*tdelta | ||
|
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||
| # DateTime uses nanosecond resolution, regardless of the resolution | ||
| # of the original date | ||
| middle.precision = 9 | ||
| # isot is ISO8601 format with "T" separating date and time and no | ||
| # time zone | ||
| argDict["date"] = DateTime(middle.tai.isot, DateTime.TAI) | ||
|
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||
| # Derive earth rotation angle from UT1 (being out by a second is not | ||
| # a big deal given the uncertainty over exactly what part of the | ||
| # observation we are needing it for). | ||
| # ERFA needs a UT1 time split into two floats | ||
| # We ignore any problems with DUT1 not being defined for now. | ||
| try: | ||
| ut1time = middle.ut1 | ||
| except iers.IERSRangeError: | ||
| ut1time = middle | ||
|
|
||
| era = erfa.era00(ut1time.jd1, ut1time.jd2) | ||
| argDict["era"] = era * radians | ||
| else: | ||
| argDict["date"] = DateTime() | ||
|
|
||
| # Coordinates | ||
| if obsInfo.tracking_radec is not None: | ||
| icrs = obsInfo.tracking_radec.transform_to("icrs") | ||
| argDict["boresightRaDec"] = SpherePoint(icrs.ra.degree, | ||
| icrs.dec.degree, units=degrees) | ||
|
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||
| altaz = obsInfo.altaz_begin | ||
| if altaz is not None: | ||
| argDict["boresightAzAlt"] = SpherePoint(altaz.az.degree, | ||
| altaz.alt.degree, units=degrees) | ||
|
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| argDict["boresightAirmass"] = obsInfo.boresight_airmass | ||
|
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| if obsInfo.boresight_rotation_angle is not None: | ||
| argDict["boresightRotAngle"] = obsInfo.boresight_rotation_angle.degree*degrees | ||
|
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| if obsInfo.boresight_rotation_coord is not None: | ||
| rotType = RotType.UNKNOWN | ||
| if obsInfo.boresight_rotation_coord == "sky": | ||
| rotType = RotType.SKY | ||
| argDict["rotType"] = rotType | ||
|
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||
| # Weather and Observatory Location | ||
| temperature = float("nan") | ||
| if obsInfo.temperature is not None: | ||
| temperature = obsInfo.temperature.to_value("deg_C", astropy.units.temperature()) | ||
| pressure = float("nan") | ||
| if obsInfo.pressure is not None: | ||
| pressure = obsInfo.pressure.to_value("Pa") | ||
| relative_humidity = float("nan") | ||
| if obsInfo.relative_humidity is not None: | ||
| relative_humidity = obsInfo.relative_humidity | ||
| argDict["weather"] = Weather(temperature, pressure, relative_humidity) | ||
|
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| if obsInfo.location is not None: | ||
| geolocation = obsInfo.location.to_geodetic() | ||
| argDict["observatory"] = Observatory(geolocation.lon.degree*degrees, | ||
| geolocation.lat.degree*degrees, | ||
| geolocation.height.to_value("m")) | ||
|
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| for key in list(argDict.keys()): # use a copy because we may delete items | ||
| if argDict[key] is None: | ||
| self.log.warn("argDict[{}] is None; stripping".format(key, argDict[key])) | ||
| del argDict[key] | ||
|
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| return VisitInfo(**argDict) |
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