Attached is a message from Bob Simon at ERD/NOAA pointing out the
inconsistencies in "data type" and "feature type" names in various
Unidata related efforts. The almost-ready CF discrete sampling proposal
has made a start at standardizing some of these names, and there is an
interest, I think, between Steve, Jon and I to extend that to other
types like grid. Essentially its a controlled vocabulary for classifying
data.
If this group is interested, I would propose a new ticket that would add
probably an Appendix that would specify this vocabulary and their
definitions. I anticipate it will be added to and clarified over time.
John
-------- Original Message --------
Subject: Re: [netcdf-java] CDM names
Date: Thu, 23 Dec 2010 08:48:41 -0700
From: John Caron <caron at unidata.ucar.edu>
To: netcdf-java at unidata.ucar.edu
Hi Bob:
Yes, you are right, there are too many forms of the "data type" and
"feature type" names, with different lineages.
1) The CF discrete sampling proposal will be the recommended one for
point data when thats finalized. Unfortunately, it will be somewhat
different from whats gone before. The CF: prefix is dropped until the
namespace proposal can be completed. So those feature types are now
proposed to be:
* *point*: one or more parameters measured at a set of points in
time and space
* *timeSeries*: a time-series of data points at the same location,
with varying time
* *trajectory*: a connected set of data points along a 1D curve in
time and space
* *profile*: a set of data points along a vertical line
* *timeSeriesProfile*: a time-series of profiles at a named location
* *trajectoryProfile*: a collection of profiles which originate
along a trajectory
The CDM will be backwards compatible, including:
* accepting the CF: prefix
* being case insensitive
* "station" and "stationTimeSeries"as aliases for "timeSeries"
* "stationProfile" as alias for "timeSeriesProfile"
* "section" as alias for "trajectoryProfile"
I know that CF wants to standardize on other feature types also. Its
hard to anticipate what they will come with, but its likely:
* grid
* swath
maybe:
* image
* radial
* unstructuredGrid
2) The DataDiscoveryAttConvention is due for another round of work, esp
in light of the ISO work that Ted and Dave have done. That might be a
good opportunity to try to reconcile.
3) I will work on the CDM library to standardize.
Thanks for bringing this up.
On 12/22/2010 4:36 PM, Bob Simons wrote:
> It is unfortunate that the CDM names listed at the sites below are all
> slightly different (different sets of names, different names for the
> same feature, different case).
> And it is unfortunate that there are two global attributes to identify
> the CDM feature/data type (#2 and #3 below).
>
> Is it possible that these could be standardized?
>
> 1)
> http://www.unidata.ucar.edu/software/netcdf-java/v4.0/javadoc/index.html
> CF.FeatureType (e.g., "stationTimeSeries")
>
> 2) The cdm_data_type global attribute:
> http://www.unidata.ucar.edu/software/netcdf-java/formats/DataDiscoveryAttConvention.html
> (e.g., "Station")
> The UAF GeoIDE project is using this
> https://nosc.ngdc.noaa.gov/dmc/swg/wiki/index.php?title=NetCDF_Attribute_Convention_for_Dataset_Discovery
>
>
> 3) The proposed CF:featureType global attribute:
> https://cf-pcmdi.llnl.gov/trac/wiki/PointObservationConventions
> section 9.8.3 (e.g., "timeSeries")
>
> 4)The THREDDS dataType types
> http://www.unidata.ucar.edu/projects/THREDDS/tech/catalog/InvCatalogSpec.html#dataType
> (e.g., "Station")
>
> Thank you for looking into this.
>
> Sincerely,
>
> Bob Simons
> IT Specialist
> Environmental Research Division
> NOAA Southwest Fisheries Science Center
> 1352 Lighthouse Ave
> Pacific Grove, CA 93950-2079
> Phone: (831)658-3205
> Fax: (831)648-8440
> Email: bob.simons at noaa.gov
>
> The contents of this message are mine personally and
> do not necessarily reflect any position of the
> Government or the National Oceanic and Atmospheric
> Administration.
> <>< <>< <>< <>< <>< <>< <>< <>< <><
>
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