"miscellaneous update"

git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@796 9d0c8265-081b-0410-96cb-a4ca84ce46f8

2 files changed, 54 insertions, 33 deletions

diff --git a/fitstopnm.html b/fitstopnm.html
index 804eeb03..3f381b52 100644
--- a/fitstopnm.html
+++ b/fitstopnm.html
@@ -29,12 +29,10 @@ space in place of the equals sign to separate an option name from its value.
 
 <p>This program is part of <a href="index.html">Netpbm</a>.
 
-<p><b>fitstopnm</b> reads a FITS file as input and produces a PPM
-image if the FITS file consists of 3 image planes (NAXIS = 3 and
-NAXIS3 = 3), or a PGM image if the FITS file consists of 2 image
-planes (NAXIS = 2), or if you specify the <B>-image</B> option.  The
-results may need to be flipped top for bottom; if so, just pipe the
-output through <B>pamflip -tb</B>.
+<p><b>fitstopnm</b> reads a FITS (Flexible Image Transport System) file as
+input and produces a PPM image if the FITS file consists of 3 image planes
+(NAXIS = 3 and NAXIS3 = 3), or a PGM image if the FITS file consists of 2
+image planes (NAXIS = 2), or if you specify the <B>-image</B> option.
 
 <P>The program tells you what kind of PNM image it is writing.
 
@@ -95,11 +93,12 @@ and quits without doing its normal job.
 
 </dl>
 
-<H2 id="references">REFERENCES</H2>
+<h2 id="notes">NOTES</h2>
 
-<p>FITS stands for Flexible Image Transport System.  A full description
-can be found in Astronomy &amp; Astrophysics Supplement Series 44 (1981),
-page 363.
+<h3 id="pixelorder">Pixel Order</h3>
+
+<p>You may need to pass the output of <b>fitstopnm</b> through <b>pamflip
+-topbottom</b>.  See <a href="pamtofits.html#pixelorder"><b>pamtofits</b></a>
 
 
 <H2 id="seealso">SEE ALSO</H2>
@@ -107,6 +106,7 @@ page 363.
 <A HREF="pamtofits.html">pamtofits</A>,
 <A HREF="pamflip.html">pamflip</A>,
 <A HREF="pgm.html">pgm</A>
+<a href="http://fits.gsfc.nasa.gov/fits_intro.html">FITS</a>
 
 <H2 id="author">AUTHOR</H2>
 
@@ -122,7 +122,10 @@ HREF="mailto:alberto@cfa.harvard.edu">alberto@cfa.harvard.edu</A>).
 <LI><A HREF="#synopsis">SYNOPSIS</A>
 <LI><A HREF="#description">DESCRIPTION</A>
 <LI><A HREF="#options">OPTIONS</A>
-<LI><A HREF="#references">REFERENCES</A>
+<LI><A HREF="#notes">NOTES</A>
+  <ul>
+  <li><a href="#pixelorder">Pixel Order</a>
+  </ul>
 <LI><A HREF="#seealso">SEE ALSO</A>
 <LI><A HREF="#author">AUTHOR</A>
 </UL>
diff --git a/pamtofits.html b/pamtofits.html
index cebb38e0..d432ddf2 100644
--- a/pamtofits.html
+++ b/pamtofits.html
@@ -6,21 +6,18 @@ Updated: 25 September 2005
 <BR>
 <A HREF="#index">Table Of Contents</A>
 
-<A NAME="lbAB">&nbsp;</A>
 <H2>NAME</H2>
 
 pamtofits - convert a Netpbm image into FITS format
 
-<A NAME="lbAC">&nbsp;</A>
-<H2>SYNOPSIS</H2>
+<H2 id="synopsis">SYNOPSIS</H2>
 
 <B>pamtofits</B>
 [<B>-max</B> <I>f</I>]
 [<B>-min</B> <I>f</I>]
 [<I>pamfile</I>]
 
-<A NAME="lbAD">&nbsp;</A>
-<H2>DESCRIPTION</H2>
+<H2 id="description">DESCRIPTION</H2>
 
 <p>This program is part of <a href="index.html">Netpbm</a>.
 
@@ -32,11 +29,7 @@ PGM image, the output file consists of a single plane image (NAXIS =
 2). If instead the input file is a PPM image, the output file will
 consist of a three-plane image (NAXIS = 3, NAXIS3 = 3).
 
-<p>You can find a full description of the FITS format in Astronomy
-&amp; Astrophysics Supplement Series 44 (1981), page 363.
-
-<A NAME="lbAE">&nbsp;</A>
-<H2>OPTIONS</H2>
+<H2 id="options">OPTIONS</H2>
 
 <p><b>-min</b> and <b>-max</b> tell <b>pamtofits</b> what &quot;physical
 values&quot; zero and maxval sample values, respectively, in the input
@@ -56,19 +49,42 @@ supposed to be used, since the input image doesn't necessarily contain
 the full possible range of sample values.  It is a conservative
 approximation.
 
+<h2 id="notes">NOTES</h2>
+
+<h3 id="pixelorder">Pixel Order</h3>
+
+<p>The FITS specification does not specify which data in the file corresponds
+to which pixel in the image (i.e. which bytes are the the top left pixel,
+etc.).  Netpbm uses the common sense, most popular arrangement: row major, top
+to bottom, left to right.  That means in a 10 wide by 20 high image, the first
+10 pixels in the file are the top row and the last 10 are the bottom row.
+Within each row, the first pixel is the leftmost one and the last pixel is
+the rightmost one.
+
+<p><b>Netpbm</b> has always done that, since it first understood the
+FITS format in 1989, so it is something of a de facto standard.
+
+<p>However, at least some versions of ImageMagick and Gimp (as seen in 2008)
+use bottom to top order, so if you use display a FITS image generated by
+<b>pamtofits</b>, it will appear upside down.  To fix that, use <b>pamflip
+-topbottom</b> on the image before feeding it to <b>pamtofits</b>.
+
+
 <h2 id="history">HISTORY</h2>
 
 <p><b>pamtofits</b> was originally <b>pnmtofits</b> and did not handle
 PAM input.  It was extended and renamed in Netpbm 10.30 (October 2005).
 
-<A NAME="lbAF">&nbsp;</A>
-<H2>SEE ALSO</H2>
+<p><b>pnmtofits</b> was itself an extension of <b>pgmtofits</b>, which
+was added to Pbmplus in 1989.
+
+<H2 id="seealso">SEE ALSO</H2>
 
 <A HREF="fitstopnm.html">fitstopnm</A>,
 <A HREF="pam.html">pam</A>
+<a href="http://fits.gsfc.nasa.gov/fits_intro.html">FITS</a>
 
-<A NAME="lbAG">&nbsp;</A>
-<H2>AUTHOR</H2>
+<H2 id="author">AUTHOR</H2>
 
 Copyright (C) 1989 by Wilson H. Bent (<A
 HREF="mailto:whb@hoh-2.att.com">whb@hoh-2.att.com</A>), with
@@ -76,16 +92,18 @@ modifications by Alberto Accomazzi (<A
 HREF="mailto:alberto@cfa.harvard.edu">alberto@cfa.harvard.edu</A>).
 
 <HR>
-<A NAME="index">&nbsp;</A>
-<H2>Table Of Contents</H2>
+<H2 id="index">Table Of Contents</H2>
 <UL>
-<LI><A HREF="#lbAB">NAME</A>
-<LI><A HREF="#lbAC">SYNOPSIS</A>
-<LI><A HREF="#lbAD">DESCRIPTION</A>
-<LI><A HREF="#lbAE">OPTIONS</A>
+<LI><A HREF="#synopsis">SYNOPSIS</A>
+<LI><A HREF="#description">DESCRIPTION</A>
+<LI><A HREF="#options">OPTIONS</A>
+<LI><A HREF="#notes">NOTES</A>
+  <ul>
+  <li><a href="#pixelorder">Pixel Order</a>
+  </ul>
 <LI><A HREF="#history">HISTORY</A>
-<LI><A HREF="#lbAF">SEE ALSO</A>
-<LI><A HREF="#lbAG">AUTHOR</A>
+<LI><A HREF="#seealso">SEE ALSO</A>
+<LI><A HREF="#author">AUTHOR</A>
 </UL>
 </BODY>
 </HTML>