Name
setpix - batch command to set pixel values from a list in
a text file
Synopsis
setpix [options] <in> [out]
Description
setpix takes a list of 2-d pixel positions and pixel val-
ues, and the name of a FITS file (a data cube, an image, a
pixel map or an ASCII list). For a given image, it goes to
all requested pixel positions and changes the pixel value
to the one requested in the list. For a cube, the process
is repeated identically over all the planes in the file.
For an ASCII list, the process is repeated over all planes
in the list and the output is a single FITS file with mul-
tiple planes (i.e. a cube).
Example:
The text file 'regions.txt' contains the following data:
----- begin regions.txt -----
#
# file: regions.txt
# defines pixels to be set
#
1 1 0.0
128 128 100.0
256 256 1000.0
----- end regions.txt -----
Using the following command:
% setpix -f regions.txt image1.fits
would make the following changes in the image
'image1.fits':
pixel value at position (1,1) is changed to 0.0
pixel value at position (128,128) is changed to 100.0
pixel value at position (256,256) is changed to 1000.0
The text file specifying pixel positions and pixel values
respects the following syntax rules:
Any line beginning with a hash (#) is a comment, thus not
processed.
Pixel positions are given as integer values. They follow
the FITS convention for pixel positions: first pixel of
the image is located at coordinates (1,1) in the lower
left corner of the image. X is increasing from left to
right, Y from bottom to top.
Pixel values are given as floating point numbers. For
pixel maps, these values are rounded up to the nearest
integer value lower than the one requested.
Default output file name for a file named 'file.fits' is
'file_set.fits'.
Options
-f regions.txt
Declares the name of the file containing pixel
positions and values. Default name for this file is
"pts.txt".
Files
Data files shall all comply with FITS format
The list of pixel positions and values is a text file,
respecting the syntax described above.