Hi John,
Thanks for your advice.
For a single vertical profile and single valued time, lat, long.
it seems there are two acceptable ways i.e 1 element vector or single valued
scalar.
Quoting from 'section 2.4 Dimensions' of CF standard:
1 element vector:
"Dimensions may be of any size, including unity. When a single value of some
coordinate applies to all the values in a variable, the recommended means of
attaching this information to the variable is by use of a dimension of size
unity with a one-element coordinate variable.
and in the next sentence a scalar:
"It is also acceptable to use a scalar coordinate variable which eliminates the
need for an associated size one dimension in the data variable."
1) ***Vector co-ordinate variables*******
Dimensions:
time=1
pressure=56
lat=1
lon=1
Variables:
time(time)
lat(lat)
lon(lon)
temperature(pressure)
2) **Scalar co-ordinate varaibles****
Dimensions:
pressure =56
Variables:
time
lat
lon
temperature(pressure)
The scalar approach you suggest as in section "H.3.3. Single profile" of the CF
v1.6 standard
is simpler than the vector approach so we will take your advice.
Regards,
Andrew
----- Original Message -----
From: "John Caron" <[email protected]>
To: "andrew walsh" <[email protected]>
Cc: <[email protected]>; "Luke Callcut" <[email protected]>;
<[email protected]>
Sent: Thursday, April 26, 2012 10:48 AM
Subject: Re: [CF-metadata] Ocean CTD data following CF Conventions v1.6
Hi andrew:
The file you sent (20110818T001140Z_M_HI504BEN.nc) appears to be a single
profile. Assuming that, you would use the following template:
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#idp8363696
note that lat, lon and time coordinates all have to be scalars.
John
On 4/18/2012 8:24 PM, andrew walsh wrote:
Hi John,
We have now constructed a real netCDF file for you to check. QC flag
variables have been added in. The QC flagging method is based on the
proposed IODE scheme in (1) below.
Attached are the sample .nc file, text (ncdump) of same and a document
specifying the CDL.
Thanks and Regards,
Andrew Walsh
Ref.
(1) Konovalov et. al (March 2012), Proposal to adopt a quality flag scheme
standard
for oceanographic and marine meteorological data, Version 1.2.
----- Original Message ----- From: "John Caron" <[email protected]>
To: "andrew walsh" <[email protected]>
Sent: Thursday, April 05, 2012 10:44 AM
Subject: Re: [CF-metadata] Ocean CTD data following CF Conventions v1.6
ok
On 4/4/2012 6:42 PM, andrew walsh wrote:
Hi John,
Thank for your offer to check a sample netCDF CTD data file. At moment we
don't have
some real .nc file but when we do I can send you a file for checking.
Andrew
----- Original Message ----- From: John Caron
To: [email protected]
Sent: Wednesday, April 04, 2012 5:55 AM
Subject: Re: [CF-metadata] Ocean CTD data following CF Conventions v1.6
Hi all:
Lets see, I havent followed the entire conversation, but:
1) Andrew if you can send me a sample file (not just the CDL) I can check
if it works in the CDM with the new 1.6 conventions, and maybe give you
some advice from my POV.
2) Aggregation in the CDM comes in 2 flavors. 1) The original
implementation simply appends multidimensional arrays together, eg "joinNew
" and "joinExisting" NCML aggregation. I call it "syntactic aggregation"
because it doesnt know what its aggregating, and the homogeneity
requirements are strict. 2) "Feature Type collections" (aka "semantic
aggregation") are the more recent development. These understand the
coordinate information of the data, and so can handle variations in the
representation, eg ragged arrays, scalar coordinates, etc. In this case,
the CDM understands a dataset as a collection of "features objects", which
can be stored in a collection of files. The interfaces to these
collections is still under development. Most current and future work in the
CDM is in this category.
John
snip ....
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