HpxMap#
- class gammapy.maps.HpxMap[source]#
Bases:
Map
Base class for HEALPIX map classes.
- Parameters:
Notes
For examples, see HEALPix-based maps
Methods Summary
create
([nside, binsz, nest, map_type, ...])Factory method to create an empty HEALPix map.
from_hdulist
(hdu_list[, hdu, hdu_bands, ...])Make a HpxMap object from a FITS HDUList.
to_hdu
([hdu, hdu_bands, sparse, format])Make a FITS HDU with input data.
to_hdulist
([hdu, hdu_bands, sparse, format])Convert to
HDUList
.Return a new map with the opposite scheme (ring or nested).
to_wcs
([sum_bands, normalize, proj, ...])Make a WCS object and convert HEALPix data into WCS projection.
Methods Documentation
- classmethod create(nside=None, binsz=None, nest=True, map_type='hpx', frame='icrs', data=None, skydir=None, width=None, dtype='float32', region=None, axes=None, meta=None, unit='')[source]#
Factory method to create an empty HEALPix map.
- Parameters:
- nsideint or
ndarray
, optional HEALPix NSIDE parameter. This parameter sets the size of the spatial pixels in the map. Default is None.
- binszfloat or
ndarray
, optional Approximate pixel size in degrees. An NSIDE will be chosen that corresponds to a pixel size closest to this value. This option is superseded by
nside
. Default is None.- nestbool, optional
Indexing scheme. If True, “NESTED” scheme. If False, “RING” scheme. Default is True.
- map_type{‘hpx’, ‘hpx-sparse’}, optional
Map type. Selects the class that will be used to instantiate the map. Default is “hpx”.
- frame{“icrs”, “galactic”}
Coordinate system, either Galactic (“galactic”) or Equatorial (“icrs”). Default is “icrs”.
- data
ndarray
, optional Data array. Default is None.
- skydirtuple or
SkyCoord
, optional Sky position of map center. Can be either a SkyCoord object or a tuple of longitude and latitude in deg in the coordinate system of the map. Default is None.
- widthfloat, optional
Diameter of the map in degrees. If None then an all-sky geometry will be created. Default is None.
- dtypestr, optional
Data type. Default is “float32”.
- regionstr, optional
HEALPix region string. Default is None.
- axeslist, optional
List of
MapAxis
objects for each non-spatial dimension. Default is None.- meta
dict
, optional Dictionary to store the metadata. Default is None.
- unitstr or
Unit
, optional The map unit. Default is “”.
- nsideint or
- Returns:
- map
HpxMap
A HEALPix map object.
- map
- classmethod from_hdulist(hdu_list, hdu=None, hdu_bands=None, format=None, colname=None)[source]#
Make a HpxMap object from a FITS HDUList.
- Parameters:
- hdu_list
HDUList
HDU list containing HDUs for map data and bands.
- hdustr, optional
Name or index of the HDU with the map data. If None then the method will try to load map data from the first BinTableHDU in the file. Default is None.
- hdu_bandsstr, optional
Name or index of the HDU with the BANDS table. Default is None.
- formatstr, optional
FITS format convention. By default, files will be written to the gamma-astro-data-formats (GADF) format. This option can be used to write files that are compliant with format conventions required by specific software (e.g. the Fermi Science Tools). The following formats are supported:
“gadf” (default)
“fgst-ccube”
“fgst-ltcube”
“fgst-bexpcube”
“fgst-srcmap”
“fgst-template”
“fgst-srcmap-sparse”
“galprop”
“galprop2”
- hdu_list
- Returns:
- hpx_map
HpxMap
Map object.
- hpx_map
- to_hdu(hdu=None, hdu_bands=None, sparse=False, format=None)[source]#
Make a FITS HDU with input data.
- Parameters:
- hdustr, optional
The HDU extension name. Default is None.
- hdu_bandsstr, optional
The HDU extension name for BANDS table. Default is None.
- sparsebool, optional
Set INDXSCHM to SPARSE and sparsify the map by only writing pixels with non-zero amplitude. Default is False.
- format{None, ‘fgst-ccube’, ‘fgst-template’, ‘gadf’}
FITS format convention. If None this will be set to the default convention of the map. Default is None.
- Returns:
- hdu_out
BinTableHDU
orImageHDU
Output HDU containing map data.
- hdu_out
- to_hdulist(hdu='SKYMAP', hdu_bands=None, sparse=False, format='gadf')[source]#
Convert to
HDUList
.- Parameters:
- hdustr, optional
The HDU extension name. Default is “SKYMAP”.
- hdu_bandsstr, optional
The HDU extension name for BANDS table. Default is None.
- sparsebool, optional
Set INDXSCHM to SPARSE and sparsify the map by only writing pixels with non-zero amplitude. Default is False.
- formatstr, optional
FITS format convention. By default, files will be written to the gamma-astro-data-formats (GADF) format. This option can be used to write files that are compliant with format conventions required by specific software (e.g. the Fermi Science Tools). The following formats are supported:
“gadf” (default)
“fgst-ccube”
“fgst-ltcube”
“fgst-bexpcube”
“fgst-srcmap”
“fgst-template”
“fgst-srcmap-sparse”
“galprop”
“galprop2”
- Returns:
- hdu_list
HDUList
The FITS HDUList.
- hdu_list
- abstractmethod to_swapped()[source]#
Return a new map with the opposite scheme (ring or nested).
- Returns:
- map
HpxMap
Map object.
- map
- abstractmethod to_wcs(sum_bands=False, normalize=True, proj='AIT', oversample=2, width_pix=None, hpx2wcs=None)[source]#
Make a WCS object and convert HEALPix data into WCS projection.
- Parameters:
- sum_bandsbool, optional
Sum over non-spatial axes before reprojecting. If False then the WCS map will have the same dimensionality as the HEALPix one. Default is False.
- normalizebool, optional
Preserve integral by splitting HEALPix values between bins. Default is True.
- projstr, optional
WCS-projection. Default is “AIT”.
- oversamplefloat, optional
Oversampling factor for WCS map. This will be the approximate ratio of the width of a HEALPix pixel to a WCS pixel. If this parameter is None then the width will be set from
width_pix
. Default is 2.- width_pixint, optional
Width of the WCS geometry in pixels. The pixel size will be set to the number of pixels satisfying
oversample
orwidth_pix
whichever is smaller. If this parameter is None then the width will be set fromoversample
. Default is None.- hpx2wcs
HpxToWcsMapping
, optional Set the HEALPix to WCS mapping object that will be used to generate the WCS map. If None then a new mapping will be generated based on
proj
andoversample
arguments. Default is None.
- Returns:
- map_out
WcsMap
WCS map object.
- map_out
- __init__(geom, data, meta=None, unit='')#
- classmethod __new__(*args, **kwargs)#