XVista manual page

NAME

bin - compress (bin) image files

SYNOPSIS

bin file [bin=] [norm] [outfile=]

DESCRIPTION

This program shrinks the data file named on the command line by the binning factor specified (2 is the default). The binning is done both in rows and columns and the data are summed. If the norm flag is specified, the pixel sum is divided by the number of pixels (the square of the binning factor).

The sum is computed as a 32 bit integer to keep significance. The binned data over-writes the input file.

The FITS header parameters BSCALE, CDELT1 and CDELT2 are changed as needed.

EXAMPLE

bin alflyr bin=4 norm

Compresses the data file alflyr by a factor of 4 (or 16 in total file size). The pixels are normalized.

The compression is normally done in the file overwriting the data, however, a new file can be specified by using the outfile= selection, however, only a minimal FITS header will be carried over.