Subject: Re: Upside Down (was Re: No ST-6 FITS images

From: mcalabre at rp.CSIRO.AU (Mark Calabretta)
Date: Fri, 15 Apr 1994 07:01:59 GMT

In article <2ohm20$i2o at darkstar.UCSC.EDU>, sla at umbra.UCSC.EDU (Steve Allen) writes:
> In article <2ohduo$dgp at gap.cco.caltech.edu>,
> Channel Energy <eychaner at SUNCUB.BBSO.CALTECH.EDU> wrote:
> >       Many FITS viewers display left to right and bottom to top (the
> >first value is in the lower left).  Is this behaviour specified by the
> >standard (I couldn't find it, but I have an older copy)?
> 
> The standard documents do not specify anything about the orientation of
> the display of a FITS image; they merely describe how it shall be stored.

The draft WCS proposal "Representations of Celestial Coordinates in FITS", by
Greisen and Calabretta (fits.cv.nrao.edu:/fits/documents/wcs) formally proposes
that pixel (1,1) be displayed at lower-left by default.  This has long been an
unwritten convention.

Mark Calabretta
ATNF