mFixNaN(1)

mFixNaN1

Replace a particular set of values in a fits image with nans (or vice-versa)

Usage

mFixNaN [-d level] [-v NaN-value] in.fits out.fits [minblank maxblank]

Overview

Converts NaNs found in the image to some other value (given by the user), or converts a range of supplied values into NaNs.

Options

-d level

Turn on debugging to the specified level (1-3)

-b

Check for non-physical boundary area (e.g. the corners of an Aitoff image) and correct them.

-v NaN-value

Value to use in place of any NaNs

Arguments

in.fits

Input FITS image file

out.fits

Path of output FITS file. To run in "count" mode without creating an output file, use a dash ("-") for this argument.

minblank maxblank

If the "-v" switch is not used, mFixNaN will replace all pixel values between minblank and maxblank with NaN.

Result

[struct stat="OK", rangeCount=rangeCount, nanCount=nanCount]

rangeCount is the number of pixels that were found between minblank and maxblank, if they were specified. If not (i.e., NaNs were removed and replaced with value), nanCount is the number of NaNs removed.

Messages

OK

[struct stat="OK", rangeCount=rangeCount, nanCount=nanCount"]

ERROR

No debug level given

ERROR

Debug level string is invalid: level

ERROR

Debug level string is invalid: level

ERROR

Debug level string cannot be negative

ERROR

No value given for NaN conversion

ERROR

NaN conversion value string is invalid: 'NaN-value'

ERROR

Invalid input file 'in.fits']

ERROR

min blank value string is not a number

ERROR

max blank value string is not a number

ERROR

Image file in.fits missing or invalid FITS

ERROR

FITS library error

Examples

A FITS image with BITPIX -64 (double-precision floating point) was generated without using NaNs; all "blank" pixels are represented by very small negative numbers. This can throw off initial attempts to display the image with a proper stretch, and does not conform to the FITS standard. To replace all those "blank" pixels with NaNs:

mFixNaN original.fits NaN.fits -4.61169e32 -4.61169e10

[struct stat="OK", rangeCount=1321, nanCount=0]

To convert those NaNs back into a single pixel value:

mFixNaN -v -4.6e32 NaN.fits blankval.fits

[struct stat="OK", rangeCount=0, nanCount=1321]

Releases

5 releases since Debian 9 (Stretch); the text changed 1 time.

  1. 9
  2. 10–13

-b since Debian 10 (Buster).

Bugs

The drizzle algorithm has been implemented but has not been tested in this release.

If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error: [struct stat="ERROR", status=207, msg="illegal character in keyword"]

It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it is safer to turn on the "level only" background matching (the "-l" flag in mBgModel.

From montage 6.1+dfsg-1+b1 in Debian 13 (Trixie). Parsed by carta from the page's man source.