FrameData

FrameData#

class astropop.framedata.FrameData(data, unit=None, dtype=None, uncertainty=None, mask=None, flags=None, use_memmap_backend=False, cache_folder=None, cache_filename=None, origin_filename=None, **kwargs)#

Bases: object

Data container for image frame to handle memmapping data from disk.

The main difference from Astropy’s CCDData is the memmapping itself. However it handles uncertainties in a totally different way. It stores only StdDev uncertainty arrays. It also stores the unit.

Parameters:

dataarray_like or Quantity: The main data values. If Quantity, unit will be set automatically. If using any quantity with masks, you must set the mask in a separate parameter.
unitUnit or string (optional): The data unit. Must be Unit compliant.
dtypestring or dtype (optional): Mandatory dtype of the data.
uncertaintyarray_like or Uncertanty or None (optional): Uncertainty of the data.
maskarray_like or None (optional): Frame mask. All the masked pixels will be flagged as PixelMaskFlags.MASKED and PixelMaskFlags.UNSPECIFIED.
flagsarray_like or None (optional): Pixel flags for the frame. See PixelMaskFlags. for values.
wcsdict, Header or WCS (optional): World Coordinate System of the image. If meta or header keys already contain WCS informations, an error will be raised.
meta or header: `dict` or `astropy.fits.Header` (optional): Metadata (header) of the frame. Only one accepted. If both are passed, error will be raised.
cache_folderstring, Path or None (optional): Place to store the cached FrameData
cache_filenamestring, Path or None (optional): Base file name to store the cached FrameData.
origin_filenamestring, Path or None (optional): Original file name of the data. If set, it will be stored in the FrameData metadata.
use_memmap_backendbool (optional): True if enable memmap in constructor.

Notes

The physical unit is assumed to be the same for data and uncertainty. So, we droped the support for data with data with different uncertainty unit, like CCDData does.
As this is intended to be a safe container for data, it do not handle builtin math operations. For math operations using FrameData, check imarith module.

Attributes Summary

`cache_filename`
`cache_folder`
`comment`	Get the FrameData stored comments.
`data`	Get the main data container.
`dtype`	Get the dta type of the data.
`flags`	Get the flags frame container.
`header`	Get the header (metadata) of the frame.
`history`	Get the FrameData stored history.
`mask`	Mask all flagged pixels.
`meta`	Get the metadata (header) of the frame.
`origin_filename`	Get the original filename of the data.
`shape`	Get the data shape following numpy.
`size`	Get the size of the data.
`uncertainty`	Get the uncertainty frame container.
`unit`	Physical unit of the data.
`wcs`	Get the World Coordinate System.

Methods Summary

`add_flags`(flag, where)	Add a given flag to the pixels in the given positions.
`astype`(dtype)	Return a copy of the current FrameData with new dtype in data.
`copy`([dtype])	Copy the current FrameData to a new instance.
`disable_memmap`()	Disable frame file memmapping (load to memory).
`enable_memmap`([filename, cache_folder])	Enable array file memmapping.
`get_masked_data`([fill_value])	Return a copy of the data with masked pixels as `fill_value`.
`get_uncertainty`([return_none])	Get the uncertainty frame in a safer way.
`mask_flags`(flags)	Get a mask pixels with an specific flag.
`mask_pixels`(pixels)	Mask pixels.
`max`()	Compute minimum value of the data.
`mean`(**kwargs)	Compute and return the mean of the data.
`median`(**kwargs)	Compute and return the median of the data.
`min`()	Compute minimum value of the data.
`statistics`()	Compute general statistics ofthe image.
`std`(**kwargs)	Compute and return the std dev of the data.
`to_ccddata`()	Convert actual FrameData to CCDData.
`to_hdu`([wcs_relax, no_fits_standard_units])	Generate an HDUList from this FrameData.
`write`(filename[, overwrite, ...])	Write frame to a fits file.

Attributes Documentation

cache_filename = None#

cache_folder = None#

comment#: Get the FrameData stored comments.

data#: Get the main data container.

dtype#: Get the dta type of the data. FrameData.data.dtype.

flags#: Get the flags frame container.

header#: Get the header (metadata) of the frame.

history#: Get the FrameData stored history.

mask#: Mask all flagged pixels. True for all masked/removed pixels.

meta#: Get the metadata (header) of the frame.

origin_filename#: Get the original filename of the data.

shape#: Get the data shape following numpy. FrameData.data.shape.

size#: Get the size of the data. FrameData.data.size.

uncertainty#: Get the uncertainty frame container.

unit#: Physical unit of the data.

wcs#: Get the World Coordinate System.

Methods Documentation

add_flags(flag, where)#

Add a given flag to the pixels in the given positions.

Parameters:

flagPixelMaskFlags: Flag to be added.
wherendarray: Positions where the flag will be added.

astype(dtype)#: Return a copy of the current FrameData with new dtype in data.

copy(dtype=None)#

Copy the current FrameData to a new instance.

Parameters:

- dtype: `~numpy.dtype` (optional): Data type for the copied FrameData. If None, the data type will be the same as the original Framedata. Default: None

disable_memmap()#: Disable frame file memmapping (load to memory).

enable_memmap(filename=None, cache_folder=None)#

Enable array file memmapping.

Parameters:

filenamestr, optional: Custom memmap file name.
cache_folderstr, optional: Custom folder to cache data.

get_masked_data(fill_value=nan)#: Return a copy of the data with masked pixels as fill_value.

get_uncertainty(return_none=True)#

Get the uncertainty frame in a safer way.

In some cases, like interfacing with QFloat, the uncertainty cannot be None or an empty container. So, in cases like this, is prefered to get a whole matrix containing zeroes. This method is responsible for this special returns. For non-empty containers, a copy in ndarray container will be returned.

Parameters:

- return_none: bool (optional): If True, an empty uncertainty frame will return only None. Else, a matrix filled with zeroes will be returned. Default: True

mask_flags(flags)#

Get a mask pixels with an specific flag.

Parameters:

flags: list of `PixelMaskFlags` or `PixelMaskFlags`

Returns:

mask: ndarray: Masked pixels. True for masked pixels.

mask_pixels(pixels)#

Mask pixels.

Parameters:

pixels: `~numpy.ndarray` or tuple: Pixels to be masked. Can be a tuple of (y, x) positions or a boolean array where True means masked. Uses the same standard as `~numpy.ndarray`[pixels] access.

max()#: Compute minimum value of the data.

mean(**kwargs)#: Compute and return the mean of the data.

median(**kwargs)#: Compute and return the median of the data.

min()#: Compute minimum value of the data.

statistics()#: Compute general statistics ofthe image.

std(**kwargs)#: Compute and return the std dev of the data.

to_ccddata()#

Convert actual FrameData to CCDData.

Returns:

CCDData: CCDData instance with actual FrameData informations.

to_hdu(wcs_relax=True, no_fits_standard_units=True, **kwargs)#

Generate an HDUList from this FrameData.

Parameters:

wcs_relax: `bool`, optional.

Allow non-standard WCS keys. Default: True

no_fits_standard_units: `bool`, optional

Skip FITS units standard for units. If this options is choose, the units will be printed in header as Unit compatible string. Default: True

**kwargs:

hdu_uncertainty: string, optional: Extension name to store the uncertainty in 2D image format.
hdu_flags: string, optional: Extension name to store the pixel list flags in table format.
unit_key: string, optional: Header key for physical unit.

Returns:

HDUList: HDU storing all FrameData informations.

write(filename, overwrite=False, no_fits_standard_units=True, **kwargs)#

Write frame to a fits file.

Parameters:

filename: str

Name of the file to write.

overwrite: bool, optional

If True, overwrite the file if it exists.

wcs_relax: `bool`, optional.

Allow non-standard WCS keys. Default: True

no_fits_standard_units: `bool`, optional

Skip FITS units standard for units. If this options is choose, the units will be printed in header as Unit compatible string. Default: True

**kwargs:

hdu_uncertainty: string, optional: Extension name to store the uncertainty in 2D image format.
hdu_flags: string, optional: Extension name to store the pixel list flags in table format.
unit_key: string, optional: Header key for physical unit.

FrameData

Contents

FrameData#