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 values, 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 multiple 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 con-
vention for pixel positions: first pixel of the image is located at
coordinates (1,1) in the lower left corner of the image. X is increas-
ing 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.