TWEAKUTILS: Utility Functions for TWEAKREG

The functions in this module support the various aspects of TweakReg, including finding the objects in the images and plotting the residuals.

Authors:: Warren Hack
License:: License

drizzlepac.tweakutils.build_pos_grid(start, end, nstep, mesh=False)[source]: Deprecated since version 3.0.0: The build_pos_grid function is deprecated and may be removed in a future version.

Return a grid of positions starting at X,Y given by ‘start’, and ending at X,Y given by ‘end’. The grid will be completely filled in X and Y by every ‘step’ interval.

drizzlepac.tweakutils.build_xy_zeropoint(imgxy, refxy, searchrad=3.0, histplot=False, figure_id=1, plotname=None, interactive=True)[source]

Deprecated since version 3.0.0: The build_xy_zeropoint function is deprecated and may be removed in a future version.

Create a matrix which contains the delta between each XY position and: each UV position.

drizzlepac.tweakutils.createWcsHDU(wcs)[source]

Generate a WCS header object that can be used to populate a reference WCS HDU.

For most applications, stwcs.wcsutil.HSTWCS.wcs2header() will work just as well.

drizzlepac.tweakutils.find_xy_peak(img, center=None, sigma=3.0)[source]: Deprecated since version 3.0.0: The find_xy_peak function is deprecated and may be removed in a future version.

Find the center of the peak of offsets

drizzlepac.tweakutils.gauss(x, sigma)[source]: Compute 1-D value of gaussian at position x relative to center.

drizzlepac.tweakutils.gauss_array(nx, ny=None, fwhm=1.0, sigma_x=None, sigma_y=None, zero_norm=False)[source]

Computes the 2D Gaussian with size nx*ny.

Parameters:

nxint
nyint [Default: None]: Size of output array for the generated Gaussian. If ny == None, output will be an array nx X nx pixels.
fwhmfloat [Default: 1.0]: Full-width, half-maximum of the Gaussian to be generated
sigma_xfloat [Default: None]
sigma_yfloat [Default: None]: Sigma_x and sigma_y are the stddev of the Gaussian functions.
zero_normbool [Default: False]: The kernel will be normalized to a sum of 1 when True.

Returns:

gauss_arrarray: A numpy array with the generated gaussian function

drizzlepac.tweakutils.idlgauss_convolve(image, fwhm)[source]: Deprecated since version 3.0.0: The idlgauss_convolve function is deprecated and may be removed in a future version.

drizzlepac.tweakutils.isfloat(value)[source]: Return True if all characters are part of a floating point value

drizzlepac.tweakutils.make_vector_plot(coordfile, columns=[1, 2, 3, 4], data=None, figure_id=None, title=None, axes=None, every=1, labelsize=8, ylimit=None, limit=None, xlower=None, ylower=None, output=None, headl=4, headw=3, xsh=0.0, ysh=0.0, fit=None, scale=1.0, vector=True, textscale=5, append=False, linfit=False, rms=True, plotname=None)[source]

Convert a XYXYMATCH file into a vector plot or set of residuals plots.

This function provides a single interface for generating either a vector plot of residuals or a set of 4 plots showing residuals. The data being plotted can also be adjusted for a linear fit on-the-fly.

Parameters:

coordfilestring: Name of file with matched sets of coordinates. This input file can be a file compatible for use with IRAF’s geomap.
columnslist [Default: [0,1,2,3]]: Column numbers for the X,Y positions from each image
datalist of arrays: If specified, this can be used to input matched data directly
titlestring: Title to be used for the generated plot
axeslist: List of X and Y min/max values to customize the plot axes
everyint [Default: 1]: Slice value for the data to be plotted
limitfloat: Radial offset limit for selecting which sources are included in the plot
labelsizeint [Default: 8] or str: Font size to use for tick labels, either in font points or as a string understood by tick_params().
ylimitfloat: Limit to use for Y range of plots.
xlowerfloat
ylowerfloat: Limit in X and/or Y offset for selecting which sources are included in the plot
outputstring: Filename of output file for generated plot
headlint [Default: 4]: Length of arrow head to be used in vector plot
headwint [Default: 3]: Width of arrow head to be used in vector plot
xshfloat
yshfloat: Shift in X and Y from linear fit to be applied to source positions from the first image
scalefloat: Scale from linear fit to be applied to source positions from the first image
fitarray: Array of linear coefficients for rotation (and scale?) in X and Y from a linear fit to be applied to source positions from the first image
vectorbool [Default: True]: Specifies whether or not to generate a vector plot. If False, task will generate a set of 4 residuals plots instead
textscaleint [Default: 5]: Scale factor for text used for labelling the generated plot
appendbool [Default: False]: If True, will overplot new plot on any pre-existing plot
linfitbool [Default: False]: If True, a linear fit to the residuals will be generated and added to the generated residuals plots
rmsbool [Default: True]: Specifies whether or not to report the RMS of the residuals as a label on the generated plot(s).
plotnamestr [Default: None]: Write out plot to a file with this name if specified.

drizzlepac.tweakutils.parse_atfile_cat(input)[source]: Return the list of catalog filenames specified as part of the input @-file

drizzlepac.tweakutils.parse_colname(colname)[source]

Common function to interpret input column names provided by the user.

This function translates column specification provided by the user into a column number.

Parameters:

colname: Column name or names to be interpreted

Returns:

colslist: The return value will be a list of strings.

Notes

This function will understand the following inputs:

'1,2,3' or   'c1,c2,c3' or ['c1','c2','c3']
'1-3'   or   'c1-c3'
'1:3'   or   'c1:c3'
'1 2 3' or   'c1 c2 c3'
'1'     or   'c1'
1

drizzlepac.tweakutils.parse_exclusions(exclusions)[source]: Read in exclusion definitions from file named by ‘exclusions’ and return a list of positions and distances

drizzlepac.tweakutils.parse_skypos(ra, dec)[source]

Function to parse RA and Dec input values and turn them into decimal degrees

Input formats could be:: [“nn”,”nn”,”nn.nn”] “nn nn nn.nnn” “nn:nn:nn.nn” “nnH nnM nn.nnS” or “nnD nnM nn.nnS” nn.nnnnnnnn “nn.nnnnnnn”

drizzlepac.tweakutils.plot_zeropoint(pars)[source]

Plot 2d histogram.

Pars will be a dictionary containing:: data, figure_id, vmax, title_str, xp,yp, searchrad

drizzlepac.tweakutils.radec_hmstodd(ra, dec)[source]

Function to convert HMS values into decimal degrees.

This function relies on the astropy.coordinates package to perform the conversion to decimal degrees.

Parameters:

ralist or array: List or array of input RA positions
declist or array: List or array of input Dec positions

Returns:

posarr: Array of RA,Dec positions in decimal degrees