[bug #58360] Disabling default blank values in integer datasets

[Mohammad Akhlaghi]

URL:
  <https://savannah.gnu.org/bugs/?58360>

                 Summary: Disabling default blank values in integer datasets
                 Project: GNU Astronomy Utilities
            Submitted by: makhlaghi
            Submitted on: Tue 12 May 2020 09:58:13 PM BST
                Category: All Gnuastro
                Severity: 3 - Normal
              Item Group: Output not reasonable
                  Status: Postponed
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any

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Details:

Unlike the NaN values in floating point format, integers don't have any
predefined defined blank value. So as explained in the blank pixels
<https://www.gnu.org/software/gnuastro/manual/html_node/Blank-pixels.html>
section of the Gnuastro book, we have adopted the following convention for
integers: for signed integers, the blank value is the smallest (most negative)
and for unsigned integers, its the maximum value.

For unsigned integers (which is usually for type for raw exposures), this is
natural because the maximum value is a saturated pixel.

But in some scenarios, this is not the desired behavior and the minimum (for
signed) or maximum (for unsigned) values actually have a meaning. We should
define a framework to disable associating blank values to integers if the user
asks. Maybe as a common option to all programs.




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