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Last modified: 21 November 2022


Bugs: reproject_image_grid


Setting the pixelsize to a value in arcseconds

If you are setting the reproject_image_grid pixelsize parameter to a value in arcseconds, you have to specify it when the tool is run, not via pset.

A feature in the CIAO parameter interface causes double quotes (") to be converted to single quotes (') when they are written to the parameter file:

unix% pset reproject_image_grid pixelsize='1"' 
unix% pget reproject_image_grid pixelsize

Supplying the pixelsize on the command line when the tool is run ensures that the value will be correctly interpreted as arcsec, e.g.

unix% reproject_image_grid pixelsize='1"' 
Input image file name (@expmaps.lis): 
.. etc. ..

The value is also correctly recorded in the history of the output file:

unix% dmhistory sn1006_expmap.fits reproject_image_grid
reproject_image_grid infile="@list_of_expmaps.lis" outfile="sn1006_expmap.fits"
xsize="2500" ysize="2500" xcenter="225.7" ycenter="-41.9" theta="0" pixelsize="1""  
projection="tan" resolution="1" method="average" coord_sys="world"  
lookupTab="/soft/ciao/data/dmmerge_header_lookup.txt" clobber="yes" verbose="0" 

Bugs fixed in CIAO 4.15

The following is a list of bugs that were fixed in the CIAO 4.15 software release.

Incorrect results when using -0 Dec in sexagesimal format

reproject_image_grid fails to correct parse the negative sign when working with -0 deg Declination values in sexagesimal format. For example

unix% reporject_image_grid in.img out.img xcenter=10:20:30 ycenter=-0:10:20 coord=world ...

This bug does not affect negative declination values greater than 0 ( -1 to -90) and does not affect values in decimal degrees.


The work around is to convert the coordinates to decimal degrees

unix% prop_precess f j/hms t j/deg p0 eval 10 20 30 -0 10 20 
155.125000    -0.172222
unix% reporject_image_grid in.img out.img xcenter=155.1250 ycenter=-0.172222 coord=world ...