sourcefinder.testutil.mock

Mock / synthetic data objects for use in testing.

Classes

Mock
SyntheticImage	Base class for accessors used with

Functions

make_wcs([crval, cdelt, crpix])

Make a WCS object for insertion into a synthetic image.

Module Contents

class sourcefinder.testutil.mock.Mock(returnvalue=None)

Bases: object

callcount = 0

callvalues = []

returnvalue = None

class sourcefinder.testutil.mock.SyntheticImage(wcs=None, data=None, beam=(1.5, 1.5, 0), freq_eff=150000000.0, freq_bw=2000000.0, tau_time=1800, taustart_ts=datetime.datetime(2015, 1, 1))

Bases: sourcefinder.accessors.dataaccessor.DataAccessor

Base class for accessors used with sourcefinder.image.ImageData.

Data accessors provide a uniform way for the ImageData class (i.e., generic image representation) to access the various ways in which images may be stored (FITS files, arrays in memory, potentially HDF5, etc.).

This class cannot be instantiated directly, but should be subclassed and the abstract properties provided. Note that all abstract properties are required to provide a valid accessor.

Additional properties may also be provided by subclasses. However, TraP components are required to degrade gracefully in the absence of these optional properties.

Attributes:

beamtuple

Restoring beam. Tuple of three floats: semi-major axis (in pixels), semi-minor axis (pixels), and position angle (radians).

centre_rafloat

Right ascension at the central pixel of the image. Units of J2000 decimal degrees.

centre_declfloat

Declination at the central pixel of the image. Units of J2000 decimal degrees.

datanumpy.ndarray

Two-dimensional numpy.ndarray of floating point pixel values.

freq_bwfloat

The frequency bandwidth of this image in Hz.

freq_efffloat

Effective frequency of the image in Hz. That is, the mean frequency of all the visibility data which comprises this image.

pixelsizetuple

(x, y) tuple representing the size of a pixel along each axis in units of degrees.

tau_timefloat

Total time on sky in seconds.

taustart_tsfloat

Timestamp of the first integration which constitutes part of this image. MJD in seconds.

urlstr

A URL representing the location of the image at the time of processing.

wcssourcefinder.utility.coordinates.WCS

An instance of sourcefinder.utility.coordinates.WCS, describing the mapping from data pixels to sky-coordinates.

Notes

The class also provides some common functionality: static methods used for parsing data files, and an ‘extract_metadata’ function which provides key info in a simple dict format.

calculate_phase_centre()

Calculate the equatorial coordinates of the center of the synthetic image, based on the image dimensions.

Returns:

tuple

A tuple containing the right ascension and declination of the image center in degrees.

beam = (1.5, 1.5, 0)

data = None

freq_bw = 2000000.0

freq_eff = 150000000.0

pixelsize

tau_time = 1800

taustart_ts

url = 'SyntheticImage'

wcs = None

sourcefinder.testutil.mock.make_wcs(crval=None, cdelt=None, crpix=None)

Make a WCS object for insertion into a synthetic image.

Args:

crvaltuple, defaultNone

Tuple of (RA, Dec) in decimal degrees at the reference position.

crpixtuple, defaultNone

Tuple of (x, y) coordinates describing the reference pixel location corresponding to the crval sky-position.

cdelttuple, defaultNone

Tuple of (cdelt0, cdelt1) in decimal degrees. This is the pixel width in degrees of arc, but not necessarily aligned to RA, Dec unless crota is (0, 0). If that is the case, then typically cdelt0 is negative since the x-axis is in the direction of West (decreasing RA).