This message came from the CF Trac system.  Do not reply.  Instead, enter your 
comments in the CF Trac system at https://cf-pcmdi.llnl.gov/trac/.

#104: Clarify the interpretation of scalar coordinate variables
-----------------------------+----------------------------------------------
  Reporter:  jonathan        |       Owner:  [email protected]
      Type:  enhancement     |      Status:  new                          
  Priority:  medium          |   Milestone:                               
 Component:  cf-conventions  |     Version:                               
Resolution:                  |    Keywords:                               
-----------------------------+----------------------------------------------
Comment (by markh):

 In [comment:40 caron], John provides us with a useful set of examples and
 remind us that there are many uses of non-gridded data which predate CF
 1.6 and the DSG implementations.  I expect many of these use cases to
 continue, not making use of the DSG featureType attribute, which I do not
 think is mandated.

 I would like to pick out one of John's examples, a definition of a
 collection of samples at a single location:

 {{{
 dimensions:
   sample = 39238923;
 variables:
   float data(sample);
     data:coordinates = "lat lon time";
   float lat;
   float lon;
   float heightAboveGround ;
   float heightAboveMsl;
   float time(sample);
 }}}

 In my naive and simple days of scalars I happily interpreted this as an
 observation collection at a point, a single location in space.

 My understanding of #104 is that, in the future, this is to be treated as
 exactly equivalent to:

 {{{
 dimensions:
   sample = 39238923;
   lat = 1;
   lon = 1;
   heightAboveGround = 1;
   heightAboveMsl = 1;

 variables:
   float data(sample);
     data:coordinates = "lat lon time";
   float lat(lat);
   float lon(lon);
   float heightAboveGround(heightAboveGround) ;
   float heightAboveMsl(heightAboveMsl);
   float time(sample);
 }}}

 This seems an odd way of representing the data to me which doesn't fit
 comfortably with the neat flexibility I have seen in use in many datasets.
 I would avoid using scalar coordinate variables under any circumstances on
 this basis.

 I am uncomfortable with this re-interpretation of John's example, I have
 numerous examples with similar characteristics.

 * How, under the terms of #104, may I represent such data, such that it
 explicitly defines 1 degree of freedom and a collection of metadata
 elements, some of which are invariant with respect to the data variable?

-- 
Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/104#comment:47>
CF Metadata <http://cf-pcmdi.llnl.gov/>
CF Metadata

This message came from the CF Trac system.  To unsubscribe, without 
unsubscribing to the regular cf-metadata list, send a message to 
"[email protected]" with "unsubscribe cf-metadata" in the body of your 
message.

Reply via email to