Dear Karl
I am not quite sure if I have understood you. I have changed ticket 85 to
propose the following for sect 9.6:
Wherever there are unused elements in data storage, the data variable and
all its auxiliary coordinate variables (spatial and time) must contain missing
values. This situation
On 4/2/2012 4:52 AM, Jim Biard wrote:
I like Jonathan's suggestion.
Fine w/ me.
- Steve
On Sat, Mar 31, 2012 at 4:19 PM, Jonathan Gregory
j.m.greg...@reading.ac.uk mailto:j.m.greg...@reading.ac.uk wrote:
Dear all
John Caron proposed
Applications should treat the data
.
-Original Message-
From: cf-metadata-boun...@cgd.ucar.edu on behalf of Jonathan Gregory
Sent: Sat 31/03/2012 21:19
To: cf-metadata@cgd.ucar.edu
Subject: Re: [CF-metadata] CF-1.6 Conformance
Requirements/Recommendations
Dear all
John Caron proposed
Applications should treat the data
Dear all
Thanks for your postings. There seems to be a consensus on this. I have
therefore changed my existing trac ticket 85 accordingly
https://cf-pcmdi.llnl.gov/trac/ticket/85
to record this consensus. Note that this means we have to amend section 9.6
as well, which explicitly disallowed
HI all,
following my previous email. I think the rules for discussed in ticket
85 should apply only to discrete sampling geometries.
Karl
On 4/2/12 1:00 PM, Jonathan Gregory wrote:
Dear all
Thanks for your postings. There seems to be a consensus on this. I have
therefore changed my
My previous email might have been blocked so here it is again:
Dear all,
I support the first paragraph, but concerning the last paragraph below, I would suggest being more explicit
about the difference between a data void and simply when there is no valid data for an
element. Also do the
Dear all
John Caron proposed
Applications should treat the data as missing where the auxiliary
coordinates are missing
and Steve proposed (an hour later, I think)
Application writers should be aware that under some (rare)
circumstances data auxiliary coordinate values may be missing,
Hi all,
Even if the missing aux coordinate values never will be found, I think
there is legitimate uses of data where some of the aux coordinate values
are missing where data values exist. For example if you want to compute
the average of data variables, you do not need the aux coordinate
I'm with you, Nan.
On Thu, Mar 29, 2012 at 10:22 AM, Nan Galbraith ngalbra...@whoi.edu wrote:
Hi All -
I agree with John Caron's wording.
It should be the responsibility of the application using auxiliary
coordinates
to respond predictably. In many cases this would mean ignoring data
Jonathan,
The point is, the information in the variable *is* coordinate information,
and there *is* a domain/range relationship between the coordinate
information and one or more measurements, even when the content of the
auxiliary coordinate variable does not (for more than one possible
reason)
Dear Jim
We are discussing auxiliary coordinate variables. They do not have to be
1D or monotonic. Those requirements apply to coordinate variables in the
Unidata sense. CF distinguishes these two concepts in Sect 1.2.
The point is, the information in the variable *is* coordinate information,
+1 to Steve's wording (that's what I was *trying* to say, Steve's is much
better).
While I agree that each application should respond predictably to this
situation, it is not the case that every application should respond the same
way, and we should not indicate that such a monolithic response
Dear all
Brian has a good point that sect 5.3 allows that there might be missing data
in aux coord variables. Appendix A - which is equally ancient in the story of
CF :-) - is not consistent with this, because it didn't allow _FillValue or
missing_value atts for coordinates until sect 9 was
Jonathan:
not to belabour , but in the interest of clarity, For GOES-R level 1 and 2
hemispheric products ...
there are non-existent points, at which the data vars have missing values and
the aux coord vars have (syntactically) valid values.
note that placing (syntactically) valid values in
Dear Randy
Thanks for the clarification. I see no problem in having missing data where
there are non-missing aux coord vars. This is a usual situation.
Best wishes
Jonathan
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The only thing that designates a variable as an auxiliary coordinate
variable is the presence of the variable name in a coordinates attribute on
another variable. There is nothing intrinsic to the variable that
designates it as a coordinate variable. (Not so for true coordinate
variables.) For
Dear Jim
The only thing that designates a variable as an auxiliary coordinate
variable is the presence of the variable name in a coordinates attribute on
another variable.
Formally, that is right. By definition, a CF aux coord var is one which is
named by a coordinates attribute. The
On 3/28/2012 6:26 AM, Jonathan Gregory wrote:
Dear all
Brian has a good point that sect 5.3 allows that there might be missing data
in aux coord variables. Appendix A - which is equally ancient in the story of
CF :-) - is not consistent with this, because it didn't allow _FillValue or
On 3/28/2012 10:49 AM, John Caron wrote:
I think we have a number of valid use cases for missing data in aux
coordinates, and i would vote to allow that.
sorry i didnt really answer jonathan's concern. I would suggest this
wording:
Auxiliary coordinates do not have to be monotonic or have
suggest the more general but applications using the auxiliary coordinates to
work with data may respond unpredictably when the auxiliary coordinates are
missing.
john
On Mar 28, 2012, at 10:07, John Caron wrote:
On 3/28/2012 10:49 AM, John Caron wrote:
I think we have a number of valid use
Hi all,
Yesterday, I briefly mentioned privately another use case for missing
data in auxiliary coordinates to Jonathan.
I have now uploaded some text and images for that case on our
wiki-server such that I can distribute it to the wider community.
See:
Folks,
There certainly are a fair number of grid featureTypes that also
would benefit from FillValues being allowed on aux coordinate
variables.
Consider this NOAA coastal ocean model grid for Chesapeake Bay:
http://screencast.com/t/Humzu7F69
and a zoom in on one of the tributaries:
Hi All,
I don't believe there was ever an intention to disallow missing values from
auxiliary coordinate variables. First, note that the definition of an
auxiliary coordinate variable in section 1.2 makes no mention of this while
it is explicit in the definition of a coordinate variable that
I was unaware of this restriction on aux coordinate variables.
On 3/26/12 4:24 AM, Jonathan Gregory wrote:
Appendix A notes that missing data is allowed in aux coord vars only in the
case of discrete sampling geometries. This means the checker could regard it as
an error also if it finds any
On 3/26/2012 2:24 AM, Jonathan Gregory wrote:
Dear Ros
Regarding this requirement:
9.6 Where any auxiliary coordinate variable contains a missing value, all
other coordinate, auxiliary coordinate and data values corresponding to that
element should also contain missing values.
Appendix A
Dear Nan and John
It's a good thing we're having this discussion! In my understanding, we have
always prohibiting missing data in aux coord vars, and in section 9 we
explicitly allowed for the first time. Evidently we should be clear, one way
or the other (which was one of the intentions of the
Folks:
Regarding the geosync request for comment .
In the case of GOES-R (and also Meteosat) our coordinate variable values are
N/S elevation angle and E/W scanning angle, which can be syntactically valid
values albeit off the disk of the earth.
However, it is very possible that there
Hi Jonathan -
For underway CTD profiles (gliders and floats, too, I'd think) if the
pressure
sensor fails intermittently, you can approximate Z by interpolating over
time, assuming there are good values along the track. In final data,
we might
do that, but we might like to present raw data
I am working with satellite data, and I, for example, have timestamps that
arrive in the data stream along with sensor measurements. I can have
independent missing values in both my time variable and my measurement
variables. I want to preserve all the incoming data, and the restriction
on true
Hi all:
From a CDM developer perspective, an auxiliary coordinate is just as
good as a regular coordinate variable. The extra requirements on
coordinate variables are helpful in knowing when to optimize, eg
monotonicity allows one to efficiently find the index given the
coordinate value.
Dear all
Regarding Randy's reply:
In the case of GOES-R (and also Meteosat) our coordinate variable values are
N/S elevation angle and E/W scanning angle, which can be syntactically valid
values albeit off the disk of the earth.
In this case, are there data values, or is the data missing
Hi all -
From a CDM developer perspective, an auxiliary coordinate is just as
good as a regular coordinate variable. The extra requirements on
coordinate variables are helpful in knowing when to optimize, eg
monotonicity allows one to efficiently find the index given the
coordinate value.
Jonathan:
We are putting in fill values for these off-earth points in the data variables.
very respectfully,
randy
Randy C. Horne (rho...@excaliburlabs.com)
Principal Engineer, Excalibur Laboratories Inc.
voice fax: (321) 952-5100
url: http://www.excaliburlabs.com
PGP Public Keys available
On 3/26/12 1:35 PM, Jonathan Gregory wrote:
...
Regarding Nan's point, I would say that we do want CF to be inclusive. It
would be a mistake to impose irrelevant requirements that deterred people
from using the convention. In the case you mention, the chapter 9 convention
for profiles wouldn't
Dear Ros
Thanks a lot for working on this. I think you have correctly identified parts
which are stated as requirements and recommendations, but you have to put
yourself in the shoes of the CF-checker, and consider what you can actually
*do* to make the checks. The CF-checker, for instance, does
Hi.
Jonathan's reply contained the section:
9.6 Where any auxiliary coordinate variable contains a missing value, all
other coordinate, auxiliary coordinate and data values corresponding to that
element should also contain missing values.
I thought I understood that missing values were
On 3/23/2012 1:59 PM, Jim Biard wrote:
Hi.
Jonathan's reply contained the section:
9.6 Where any auxiliary coordinate variable contains a missing
value, all
other coordinate, auxiliary coordinate and data values
corresponding to that
element should also contain missing
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