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<p>I think you are misreading. Tricky 0-based vs. 1-based?</p>
<p> In this example pixel 0 (FITS convention, which is just
outside the grid) has value 0, pixel 1 , the first one, has value
1 and pixel 2 is 2.<br>
</p>
<div class="moz-cite-prefix">On 2/15/23 09:46, Patrick Leahy via
fitswcs wrote:<br>
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<p class="MsoNormal">Hi Folks,<o:p></o:p></p>
<p class="MsoNormal"> Not sure if this is the
right list, but there is currently a discussion going on about
the right way to store Faraday synthesis spectra and spectral
cubes, which are complex-valued. One way is to use a COMPLEX
axis as discussed in WCS paper I (and the original FITS
papers). But there seems to be a long-standing inconsistency
in the FITS standard on this point. All references agree that
COMPLEX value 1 is real and 2 is complex. But the example of
this in the standard, Table 28, is:<o:p></o:p></p>
<p class="MsoListParagraph">SIMPLE=T <o:p></o:p></p>
<p class="MsoListParagraph">BITPIX=32 <o:p></o:p></p>
<p class="MsoListParagraph">NAXIS=2 <o:p></o:p></p>
<p class="MsoListParagraph">NAXIS1=2 <o:p></o:p></p>
<p class="MsoListParagraph">NAXIS2=100 <o:p></o:p></p>
<p class="MsoListParagraph">CTYPE1='COMPLEX' <o:p></o:p></p>
<p class="MsoListParagraph">CRVAL1=0. <o:p></o:p></p>
<p class="MsoListParagraph">CRPIX1=0. <o:p></o:p></p>
<p class="MsoListParagraph">CDELT1=1. <o:p></o:p></p>
<p class="MsoListParagraph">END<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoNormal">Here the complex axis runs from 0 to 1, not
1 to 2 as expected. Is this a mistake or am I misreading?
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal"> Paddy Leahy<o:p></o:p></p>
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<br>
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