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<p><tt>On 6/1/2016 11:14 AM, Demitri Muna wrote:
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There is a significant difference between documenting use of
the FITS format and incorporating it into the standard. As an
example, I recently came across UV data, which immediately
crashed my FITS viewer, and then this in the AIPS File Format
Memo:
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<p class=""><span style="font-size: 10.000000pt;
font-family: 'CMR10'" class="">In the UV-tables
form, the visibility data are written as a FITS
binary table, normally placed after the other
table extensions. The primary HDU has an </span><span
style="font-size: 10.000000pt; font-family:
'CMSY10'" class="">AIPS </span><span
style="font-size: 10.000000pt; font-family:
'CMR10'" class="">conventional form meant
primarily to be so odd as to
act as a reliable identifier. The primary HDU
asserts that the primary data has two axes, the
first of which
has 777777701 values while the second has zero
values. This is su</span><span style="font-size:
10.000000pt; font-family: 'CMR10'" class="">ffi</span><span
style="font-size: 10.000000pt; font-family:
'CMR10'" class="">cient to tell all FITS readers
that the
primary data set is not a random groups data set
and otherwise contains no data. </span></p>
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<div class="">This may be convention, but it's *lying*. I'm
sure that there are untold numbers of FITS files of UV data
that use this convention. Should it be part of the standard?
Absolutely not.</div>
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<tt>It is legal for a FITS image to have one or more zero length
axes as well as other non-zero length axes, so these UV visibility
data do conform to the requirements of the FITS standard and are
not lying. One could say that these 2D images really are
777777701 pixels wide, but because they are 0 pixel high they are
hard to see. :-)<br>
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'CMR10'" class=""></span></tt><br>
-Bill<br>
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