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Jim --
I like your summary. Based on that, here is what I see are the
specific points we need to propose (after we all agree on them, of
course):
1. several "standard_names" to accommodate our domain. From your CDL example:
a. the_image (I am not in favor of this, but to answer Tom
Rink's question about when you have single-banded data, I think it is
essential to define a standard_name for "satellite image data")
b. band
c. radiation_polarization
d. radiation_bandwidth
e. radiation_central_wavelength
2. a new axis type that uniquely identifies this "dimension variable"
as such. I am concerned with John's declaration that coordinate
variables need to be monotonically increasing, because as has been
pointed out by you and Tom Rink, that is not always the case.
However, in your example, you use a sort of generic "index" as the
"axis type" -- I like that since it then allows for other variables to
be used as appropriate for the data.
I will look forward to hearing from other data providers, and John
Caron about the appropriateness of this idea. Thanks again for
putting this together, as it will be important to have several
examples on hand for people to refer to....
tom
On Tue, Jul 26, 2011 at 8:19 AM, Jim Biard <Jim.Biard@xxxxxxxx> wrote:
> Hi.
>
> I thought it might be useful to throw out a very rough draft of the sort of
> thing I think we are talking about for representing bands. So here is a bit
> of CDL.
>
> netcdf file:/san3/npp/jbiard/NcmlSamples/band_ideas.ncml {
> dimensions:
> bandit = 4;
> lines = 5000;
> samples = 5000;
> variables:
> float image(bandit=4, lines=5000, samples=5000);
> :coordinates = "bandit polarization wavelength bandwidth";
> :units = "W m-2";
> :long_name = "the image";
> :standard_name = "the_image";
> short bandit(bandit=4);
> :axis = "index";
> :long_name = "band";
> :standard_name = "band";
> float wavelength(bandit=4);
> :coordinates = "bandit";
> :units = "um";
> :long_name = "center wavelength";
> :standard_name = "radiation_center_wavelength";
> float bandwidth(bandit=4);
> :coordinates = "bandit";
> :units = "um";
> :long_name = "bandwidth";
> :standard_name = "radiation_bandwidth";
> short polarization(bandit=4);
> :coordinates = "bandit";
> :units = "radians";
> :long_name = "polarization";
> :standard_name = "radiation_polarization";
> }
>
> --
> Jim Biard
>
> Government Contractor, STG Inc.
> Remote Sensing and Applications Division (RSAD)
> National Climatic Data Center
> 151 Patton Ave.
> Asheville, NC 28801-5001
>
> jim.biard@xxxxxxxx
> 828-271-4900
>
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--
Tom Whittaker
University of Wisconsin-Madison
Space Science & Engineering Center (SSEC)
Cooperative Institute for Meteorological Satellite Studies (CIMSS)
1225 W. Dayton Street
Madison, WI 53706 USA
ph: +1 608 262 2759
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