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0.1.119 simanalyze

Requires:

Synopsis
image and analyze measurement sets created with simobserve

Description

This task is for imaging and analyzing measurement sets (MSs) simulated with simobserve or simalma.

Arguments





Inputs

project

root prefix for output file names

allowed:

string

Default:

sim

image

(re)image project. * .mstoproject.image

allowed:

bool

Default:

True

imagename

simulation output image to analyze (default = first $project/*.image found)

allowed:

string

Default:

default

skymodel

skymodel image to analyze (the .skymodel image created by simobserve or simalma and used by one of those tasks to create an MS; if unspecified, will try to find one similar to your specified output image name)

allowed:

string

Default:

vis

Measurement Set(s) to image

allowed:

string

Default:

default

modelimage

lower resolution prior image to use in clean e.g. existing total power image

allowed:

string

Default:

imsize

output image size in pixels (x,y) or 0 to match model

allowed:

intArray

Default:

00

imdirection

set output image direction, (otherwise center on the model)

allowed:

string

Default:

cell

cell size with units e.g. ”10arcsec” or ”” to equal model

allowed:

string

Default:

interactive

interactive clean? (make sure to set niter>0 also)

allowed:

bool

Default:

False

niter

maximum number of iterations (0 for dirty image)

allowed:

int

Default:

0

threshold

flux level (+units) to stop cleaning

allowed:

string

Default:

0.1mJy

weighting

weighting to apply to visibilities. briggs will use robust=0.5

allowed:

string

Default:

natural

mask

Cleanbox(es), mask image(s), region(s), or a level

allowed:

any

Default:

variant

outertaper

uv-taper on outer baselines in uv-plane

allowed:

stringArray

Default:

pbcor

correct the output of synthesis images for primary beam response?

allowed:

bool

Default:

True

stokes

Stokes params to image

allowed:

string

Default:

I

featherimage

image (e.g. total power) to feather with new image

allowed:

string

Default:

analyze

(only first 6 selected outputs will be displayed)

allowed:

bool

Default:

False

showuv

display uv coverage

allowed:

bool

Default:

True

showpsf

display synthesized (dirty) beam (ignored in single dish simulation)

allowed:

bool

Default:

True

showmodel

display sky model at original resolution

allowed:

bool

Default:

True

showconvolved

display sky model convolved with output clean beam

allowed:

bool

Default:

False

showclean

display the synthesized image

allowed:

bool

Default:

True

showresidual

display the clean residual image (ignored in single dish simulation)

allowed:

bool

Default:

False

showdifference

display difference between output cleaned image and input model sky image convolved with output clean beam

allowed:

bool

Default:

True

showfidelity

display fidelity (see help)

allowed:

bool

Default:

True

graphics

display graphics at each stage to [screen—file—both—none]

allowed:

string

Default:

both

verbose

allowed:

bool

Default:

False

overwrite

overwrite files starting with $project

allowed:

bool

Default:

True

dryrun

only print information [experimental; only for interfermetric data]

allowed:

bool

Default:

False

logfile

allowed:

string

Default:

Returns
void

Example

 
      * "project" needs to be the directory of results generated by running  
        simobserve or simalma. In particular $project/$project.skymodel  
        will be required in order to compare output and input images.  
 
    -------------------------------  
    mode image=True:  
      * One should input one or more simulated MSs using the "vis" parameter.  
        These can include a total power MS.  
        Simanalyze will grid any total power MS,  
        clean (invert and deconvolve) any interferometric MSs,  
        and feather the results.  
 
      * the "vis" parameter:  
        - example: single MS: vis="mysim.alma.out03.ms"  
        - example: multiple MSs: vis="mysim.alma.out03.ms,mysim.aca.tp.ms"  
        - one can use ’$project’ and let the task automatically replace it with  
          the project name, e.g., vis="$project.noisy.ms,$project.noisy.sd.ms".  
          However, note that if you created measurement set(s) using simobserve,  
          MS names will include the configuration, e.g.  
          $project.alma_out20.noisy.ms  
        - setting "vis" to "default" will find and attempt to image  
          all measurement sets (interferometric and single dish) in the  
          project directory  
 
      * Sometimes it is preferable to grid the single dish MS using the  
        sdimaging task for more control.  In that case one can input  
        the resulting single dish imaging under "featherimage", only  
        put interferometric MSs in "vis", and simanalyze  will clean the  
        interferometric and feather with your "featherimage".  
 
      * Sometimes it is preferable to use a low resolution (single dish or  
        synthesis) image as a prior model during clean deconvolution  
        of a higher resolution interferometric MS.  That is accomplished  
        by putting the low-resolution image in "modelimage" and the MS  
        to be deconvolved in "vis". NOTE: This is not the original skymodel  
        that was used in simobserve or simalma.  It is recommended to  
        leave this blank unless the user is familiar with using a prior  
        in clean deconvolution. (see casaguides) NOTE 2: modelimage will  
        not be used if the MS to be imaged is total power.  
 
      * uses Cotton-Schwab clean for single fields and Mosaic gridding  
        for multiple fields (with Clark PSF calculation in minor cycles).  
 
      * interactive clean or use of more parameters than the subset  
        visible here are available by simply running the clean task directly,  
        then using simanalyze in the mode image=False (see below).  
 
      * if graphics are turned on, this step will display the clean image  
        and residual image  
 
      * the "mask" parameter:  
        Specification of cleanbox(es), mask image(s), primary beam  
        coverage level, and/or region(s) to be used for cleaning.  
        clean tends to perform better, and is less likely to diverge, if  
        the clean component placement is limited by a mask to where real  
        emission is expected to be.  e.g. pixel ranges mask=[110,110,150,145],  
        filename of mask image mask=’myimage.mask’, or a file with mask  
        regions --  see help for the clean task for more information.  
 
      * NOTE: simanalyze was designed to be used after one or more runs of  
        simobserve, and as such it assumes it will be able to find a  
        sky model image called $project/$project.skymodel, .newmodel, or  
        .compskymodel in the $project/ subdirectory.  If the simulated  
        MS has been created by means other than simply calling simobserve,  
        the user may have to copy their sky model image into the $project  
        subdirectory and call it "$project.skymodel"  
 
    -------------------------------  
    mode image=False:  
      * Sometimes the user has created a synthesized image themselves,  
        most likely using the clean task, perhaps along with  
        sdimaging and feather, or a previous call to simanalyze with image=True  
      * The user should input that simulated image as "imagename".  
        It will have suffix .image if created by clean, simanalyze, or simalma  
      * simanalyze will attempt to find an appropriate skymodel image -  
        this is the *.skymodel image created by simobserve or simalma,  
        the (optionally rescaled) original sky model, which was used  
        to create the measurement set.  
        simanalyze will look in the project directory, but if there are  
        multuple skymodels present it may not find the right one, so the  
        "skymodel" parameter allows explicit specification.  
 
    -------------------------------  
    mode analyze=True is used to create an image of the difference between  
        the input skymodel and the simulated output image (whether that output  
        image is being generated in the same call to simanalyze, with  
        image=True, or has already been generated, and simanalyze is being  
        called with image=False).  
 
    showuv -- display uv coverage  
    showpsf -- display synthesized (dirty) beam (ignored in single dish simulation)  
    showmodel -- display sky model at original resolution  
    showconvolved -- display sky model convolved with output beam  
    showclean -- display the synthesized image  
    showresidual -- display the clean residual image (ignored in single dish simulation)  
    showdifference -- display difference between output cleaned image and  
         input model sky image convolved with output clean beam  
    showfidelity -- display fidelity image  
         fidelity = abs(input) / max[ abs(input-output), 0.7*rms(output) ]  
 
 
    Note that the RMS is calculated in the lower quarter of the image.  
         This is likely not the best choice, so you are encouraged to  
         measure RMS yourself in an off-source region using the viewer.  
 
    dryrun=True is an advanced technical mode only useful for interferometric  
         (not single dish) data.  
 
    -------------------------------  
    Output produced: (not all will always exist, depending on input parameters)  
    To support different runs with different arrays, the names have the  
    configuration name from antennalist appended.  
    -------------------------------  
    project.[cfg].skymodel.flat.regrid.conv = input sky regridded to match  
         the output image, and convolved with the output clean beam  
 
    project.[cfg].image = synthesized image  
    project.[cfg].flux.pbcoverage = primary beam correction for mosaic image  
    project.[cfg].residual = residual image after cleaning  
    project.[cfg].clean.last = parameter file of what parameters were used in  
          the clean task  
    project.[cfg].psf = synthesized (dirty) beam calculated from weighted uv  
          distribution  
    project.[cfg].image.png = diagnostic figure of clean image and residual  
 
    project.[cfg].fidelity = fidelity image  
    project.[cfg].analysis.png = diagnostic figure of difference and fidelity  
 
    project.[cfg].simanalyze.last = saved input parameters for simanalyze task  
 
    -------------------------------  
    Please see http://casaguides.nrao.edu, and contact the CASA helpdesk  
    with questions.  


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