changesex(1) --- Imcat Users Guide --- section: imtools --- last changed: Thu Jul 10 HST
changesex - switch byte order of a FITS fileSYNOPSIS
changesex [-u] [-n]DESCRIPTION
The filter "changesex" swaps the byte order in a fits image.
Imcat commands can work with either big- or little-endian images. Since 2/99 imcat written images contain a header value with keyword BYTEORDR whose value can be either BIG_ENDIAN or LITTLE_ENDIAN, and the value of which is set by the presence or absence of the environment variable IMCATSWAPFITSBYTES. If IMCATSWAPFITSBYTES is set then the image is stored in non-native byte order. Non-imcat images are assumed to be BIG_ENDIAN, while pre 2/99 imcat images are assumed to be in the native byte order. If you have set IMCATSWAPFITSBYTES then you will need to filter old style images through 'changesex' to bring them into non-native order. Use 'changesex -n' to force images with BYTEORDR=LITTLE_ENDIAN to BIG_ENDIAN format for compatibility with non-imcat software. AUTHOR
Nick Kaiser: kaiser@hawaii.edu