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Last modified: 26 October 2016

URL: http://cxc.harvard.edu/ciao/bugs/dmextract.html

Bugs: dmextract


Table of Contents

Bugs


Bugs

dmextract requires a "sky" vector to bin on x and y

If the x and y columns are not associated as a "sky" vector, dmextract can't bin on them:

unix% dmextract infile="img.fits[bin (X,Y)=@ann.reg]" ...

# dmextract (CIAO): dsDMEXTRACTREGWCSWERR -- WARNING: Expected 2 dimensions for the sky descriptor. Skipping translation of region to WCS. 
or
# dmextract (CIAO): dsFINDCOLUMNERR -- ERROR: Column 'sky' was not found
in file 'HDU2'.

Workaround:

Edit the file header to create a sky vector.

unix% cat dmhedit.lis
#add
MTYPE1 = POS
MFORM1 = X,Y

unix% punlearn dmhedit
unix% dmhedit img.fits dmhedit.lis

Problem with pgrid() stack syntax

There is a problem using the pgrid() stack syntax when making radial profiles.

unix% dmextract "image.fits[sky=pgrid(4096,4096,0:1000:100,30:60:30)]" sector.fits opt=generic

While the tool runs to completion, the output is not always correct.

Binning on celestial coordinates

Trying to bin on celestial coordinates can yield incorrect results

% dmextract "events.fits[bin cel=circle(150.57256,2.4995918,0.09')]" outfile=/tmp/test.fits op=generic

which may produce an incorrect radius column.

Users should only bin in physical or logical coodinates.


Last modified: 26 October 2016
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