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<font face="Times New Roman">Hi Jamie,<br>
<br>
Well, I really think large chunks of contiguous missing
time-slices should be treated differently from occasional missing
time-slices.<br>
<br>
In the latter case, your argument has merit in that if we allow
flexibility, users would have to perform 2 rather than 1 test. I
have just checked with Charles and found out that CMOR will error
exit if you try to write successive time-slices to a file that are
not spaced within 20% of the specified interval. So if you try to
write monthly data and skip a month, CMOR will error exit. CMOR
can't check whether time-slices are missing *between* two files.
<br>
<br>
Anyway, as a practical matter then, most users will have to fill
time-slices that can't be recovered with missing values or CMOR
will error exit. So, I guess I vote to drop the 2nd option I
proposed. Thus, you shouldn't omit isolated time-slices entirely;
you should fill them with missing values.<br>
<br>
[Large chunks of contiguous missing time-slices can be omitted by
constructing files such that the missing time-slices fall between
files.]<br>
<br>
Any objections?<br>
<br>
Best regards,<br>
Karl<br>
<br>
</font><br>
On 6/27/11 9:15 AM, Kettleborough, Jamie wrote:
<blockquote
cite="mid:E51EDFEBF10BE44BB4BDAF5FC2F024B90250C92C@EXXMAIL02.desktop.frd.metoffice.com"
type="cite">
<pre wrap="">Hello Karl,
Is this extra flexibility really needed? I think that giving
alternative 'representations' of the fact that some data sets have
unavailable time slices may make it harder for the data user. Don't
they have to write code to deal with all the alternatives?
Sorry this is so terse and there are other things in your e-mail I
haven't commented on - because I haven't had chance to think through
what you are saying. I'm also aware you need to get a decision made on
this so you can inform people what to do.
Jamie
</pre>
<blockquote type="cite">
<pre wrap="">So, I'm inclined to allow some flexibility summarized here
since unless folks are careful, they'll make mistakes no
matter what we decide:
When isolated time-slices in a dataset are lost and it is
impossible to recover them, it is recommended that those
isolated missing time-slices be:
1) filled entirely with the "missing data" value, or
2) be entirely omitted from the file (making sure the
time-coordinate reflects their absence)
When significant portions of a time-series are omitted
(either my design or otherwise), one should simply not create
files for those portions of the time-series. This might
require the user to divide data normally found in a single
file into two files. For example, if 100-years of monthly
mean data are normally packaged into a single file, but a
decade (i.e., 120 consecutive samples) is unavailable (say
years 40-49), the user should write instead two files, the
first with 40 years of day and the second with the last 50
years of data.
Further discussion invited.
</pre>
</blockquote>
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</pre>
</blockquote>
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