File frameSetUtils.h

namespace lsst

Class for a simple mapping implementing a generic AstrometryTransform.

Remove all non-astronomical counts from the Chunk Exposure’s pixels.

Forward declarations for lsst::utils::Cache

For details on the Cache class, see the Cache.h file.

It uses a template rather than a pointer so that the derived classes can use the specifics of the transform. The class simplePolyMapping overloads a few routines.

A base class for image defects

Numeric constants used by the Integrate.h integrator routines.

Compute Image Statistics

Note

Gauss-Kronrod-Patterson quadrature coefficients for use in quadpack routine qng. These coefficients were calculated with 101 decimal digit arithmetic by L. W. Fullerton, Bell Labs, Nov 1981.

Note

The Statistics class itself can only handle lsst::afw::image::MaskedImage() types. The philosophy has been to handle other types by making them look like lsst::afw::image::MaskedImage() and reusing that code. Users should have no need to instantiate a Statistics object directly, but should use the overloaded makeStatistics() factory functions.

namespace afw
namespace geom
namespace detail

Functions

std::shared_ptr<ast::FrameSet> readFitsWcs(daf::base::PropertySet &metadata, bool strip = true)

Read a FITS convention WCS FrameSet from FITS metadata

The resulting FrameSet may be any kind of WCS supported by FITS; if it is a celestial WCS then 1,1 will be the lower left corner of the image (the FITS convention, not the LSST convention).

This routine replaces RADECSYS with RADESYS if the former is present and the latter is not, since that is a common misspelling in FITS headers.

The returned FrameSet will have an IWC (intermediate world coordinate system) frame.

Parameters

  • [inout] metadata: FITS header cards

  • [in] strip: If true: strip items from metadata used to create the WCS, such as RADESYS, EQUINOX, CTYPE12, CRPIX12, CRVAL12, etc. Always keep keywords that might be wanted for other purpposes, including NAXIS12 and date-related keywords such as “DATE-OBS” and “TIMESYS” (but not “EQUINOX”).

Exceptions

  • pex::exceptions::TypeError: if the metadata does not contain a FITS-WCS

std::shared_ptr<ast::FrameDict> readLsstSkyWcs(daf::base::PropertySet &metadata, bool strip = true)

Read an LSST celestial WCS FrameDict from a FITS header.

Calls getImageXY0FromMetadata to determine image XY0.

Saves CRVAL by setting the output SkyFrame’s SkyRef to CRVAL and SkyRefIs=”Ignore” (so SkyRef is not treated as an offset).

The frames of the returned WCS will be as follows:

  • ”PIXELS” (base frame): pixel frame with 0,0 the lower left corner of the image (LSST convention)

  • ”IWC”: FITS WCS intermediate world coordinate system

  • ”SKY” (current frame): an ast::SkyFrame with domain “SKY”: ICRS RA, Dec

Warning

Does not compensate for the offset between a subimage and its parent image; callers must do that manually, e.g. by calling SkyWcs::copyAtShiftedPosition.

Warning

the general SkyWcs generated by LSST software cannot be exactly represented using standard WCS FITS cards, and so this function cannot read those. This function is intended for two purposes:

  • Read the standard FITS WCS found in raw data and other images from non-LSST observatories and convert it to the LSST pixel convention.

  • Read the approximate FITS WCS that LSST writes to FITS images (for use by non-LSST code).

All frames are instances of ast::Frame except the SKY frame. All have 2 axes.

Parameters

  • [inout] metadata: FITS header cards

  • [in] strip: If true: strip items from metadata used to create the WCS, such as RADESYS, EQUINOX, CTYPE12, CRPIX12, CRVAL12, etc. Always keep keywords that might be wanted for other purpposes, including NAXIS12 and date-related keywords such as “DATE-OBS” and “TIMESYS” (but not “EQUINOX”).

Exceptions

  • lsst::pex::exceptions::TypeError: if the metadata does not describe a celestial WCS.

std::shared_ptr<daf::base::PropertyList> getPropertyListFromFitsChan(ast::FitsChan &fitsChan)

Copy values from an AST FitsChan into a PropertyList

Warning

COMMENT and HISTORY cards are treated as string values

Exceptions

  • lsst::pex::exceptions::TypeError: if fitsChan contains cards whose type is not supported by PropertyList: complex numbers, or cards with no value

ast::FitsChan getFitsChanFromPropertyList(daf::base::PropertySet &metadata, std::set<std::string> const &excludeNames = {}, std::string options = "")

Construct AST FitsChan from PropertyList

Return

an ast::FitsChan representing this PropertyList

Parameters

  • [in] metadata: Metadata to transfer; if this is a PropertyList then the order of items is preserved.

  • [in] excludeNames: Names of entries to exclude from the returned header string.

  • [in] options: Options string to pass to ast::FitsChan constructor.