Hi John,
1. I wanted to use an example from a nc4 conventions presentation, in situ observations:
types:
compound obs_t {
float pressure ;
float temperature ;
float salinity ;
}
obs_t observations_t(*) ; // a variable number of observations
compound sounding_t {
float latitude ;
float longitude ;
int time;
obs_t obs;
}
sounding_t soundings_t(*) ; // a variable number of soundings
compound track_t {
string id ;
string description ;
soundings_t soundings;
}
This is not implemented in the Java API, yet.
2. I think trajectory is when you follow a set of "things", boats, a person. But at each time step they are identical, maybe not the same number because of missing data. I could assume that I have a trajectory but actually I can't be sure if my particles are the same as before. Therefore I chose not to take that convention.
I'll be happy to contribute to the discussion as well as good as I can!
Best regards,
Ute
Ute Br?nner
www.sintef.com/marine_environment
? Consider the environment before printing
-----Original Message-----
From: John Caron [mailto:caron at unidata.ucar.edu]
Sent: Dienstag, 12. Oktober 2010 19:31
To: Rich Signell
Cc: Ute Br?nner; Jonathan Gregory; cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] point observation data in CF 1.4
Hi Ute:
1. im not sure what this means: " I now finally find out that the new
approaches of Netcdf 4 are not implemented in the Java API, yet."
2. I would have thought "3D particle tracking" would be a trajectory.
how is it different?
John
On 10/11/2010 4:24 AM, Rich Signell wrote:
> Ute,
>
> I was thinking that you could use the proposed convention in 9.3.2 as
> a workaround, with the "station" being each record. But I see now
> that the coordinate variables for lon, lat need to be a function of
> station, so as you say, that won't work.
>
> Clearly there is a need for another Point Convention type to handle
> the output from particle tracking models like this. I can think of at
> least four models that would benefit from this convention right now,
> including the NSF RAPID grant we are working on for 3D particle
> tracking using LTRANS for the Deepwater Horizon Spill.
>
> _at_Jonathan, Caron& Hankin: Can we revive your discussion? I'd be
> happy to participate.
>
> -Rich
>
> On Mon, Oct 11, 2010 at 4:05 AM, Ute Br?nner<Ute.Broenner at sintef.no> wrote:
>> Hei Rich,
>>
>> I found that convention before, this was what I mentioned to Jonathan.
>> But first of all, this is not convention, yet, and secondly I have no stations but a varying set of observations per timestep (neither stations nor trajectories). I now write the data with redundant time as a limited dimension, and records(time, latitude, longitude) and have
>> mass (record), radius(record) etc.
>>
>> Thanks anyway,
>> Ute
>>
>> Ute Br?nner
>> www.sintef.com/marine_environment
>>
>> ? Consider the environment before printing
>>
>> -----Original Message-----
>> From: rsignell at gmail.com [mailto:rsignell at gmail.com] On Behalf Of Rich Signell
>> Sent: Freitag, 8. Oktober 2010 13:59
>> To: Ute Br?nner
>> Cc: Jonathan Gregory; cf-metadata at cgd.ucar.edu; John Caron
>> Subject: Re: [CF-metadata] point observation data in CF 1.4
>>
>> Ute,
>>
>> On this page:
>> https://cf-pcmdi.llnl.gov/trac/wiki/PointObservationConventions
>>
>> It appears that your case *might* be handled by:
>>
>> 9.3.2 Ragged array (contiguous) representation
>>
>> I'm pretty sure that this "ragged_row_count" feature *is* included in
>> NetCDF-Java, but John Caron (cc'd here) could confirm.
>>
>> Please report back to this group if you find success (or perhaps even
>> if you don't!)
>>
>> Thanks,
>> -Rich
>>
>> On Thu, Oct 7, 2010 at 3:15 AM, Ute Br?nner<Ute.Broenner at sintef.no> wrote:
>>> Jonathan,
>>> thanks for your answer! My troubles were related to shape and dimensions.
>>> I now finally find out that the new approaches of Netcdf 4 are not implemented in the Java API, yet.
>>> I now use a record dimension which is unlimited and a limited time dimension. Hope that works, otherwise, I have your address now :-)
>>>
>>> Best regards,
>>> Ute
>>>
>>> Ute Br?nner
>>> www.sintef.com/marine_environment
>>>
>>> ? Consider the environment before printing
>>>
>>> -----Original Message-----
>>> From: Jonathan Gregory [mailto:jonathan at met.reading.ac.uk] On Behalf Of Jonathan Gregory
>>> Sent: Mittwoch, 6. Oktober 2010 19:13
>>> To: Ute Br?nner
>>> Cc: cf-metadata at cgd.ucar.edu
>>> Subject: [CF-metadata] point observation data in CF 1.4
>>>
>>> Dear Ute
>>>
>>> You are right, the convention for timeseries of different lengths being
>>> contained in one variable is not yet agreed. Some months ago John Caron, Steve
>>> Hankin and I discussed it at length but did not quite manage to finish it,
>>> unfortunately. So there isn't a CF convention for it at the moment.
>>>
>>>> but I have some trouble in writing the data.
>>> What kind of trouble?
>>>
>>> Best wishes
>>>
>>> Jonathan
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>
>>
>> --
>> Dr. Richard P. Signell (508) 457-2229
>> USGS, 384 Woods Hole Rd.
>> Woods Hole, MA 02543-1598
>>
>
>
Received on Wed Oct 13 2010 - 00:40:07 BST
