Jim,
Awesome. And I guess if we save it as netcdf4 with deflation, it doesn't
really matter how large we make the maximum number of vertices because all
those fillValues at the end will compress very well.
I'm still interested in why we switched from "cell_bounds" to "bounds", if
indeed we did.
Thanks,
Rich
On Fri, Sep 19, 2014 at 4:53 PM, Jim Biard <jbiard at cicsnc.org> wrote:
> Richard,
>
> You can do this. Assuming you are storing the time series for more than
> one watershed, you would have something like this (I lifted this largely
> from Sections 7.1 and 7.2 in the CF Conventions document):
>
> dimensions:
> time = -1;
> sheds = 20;
> npoly_verts = 2000; // This would be set to the maximum number of
> vertices for any watershed.
> variable:
> float precip(time, sheds);
> precip.cell_measures = "area: watershed_areas";
> precip.cell_methods = "time area: sum"
> precip.coordinates = "lat lon";
>
> time(time);
> time.axis = "T";
> time.standard_name = "time";
> time.units = "days since ?????";
> time.bounds = "time_bnds";
>
> float lon(cell); // This variable will contain a longitude to
> associate with each watershed. Perhaps the center.
> lon.standard_name = "longitude";
> lon.units = "degrees_east";
> lon.bounds = "watershed_lons";
>
> float lat(cell); // This variable will contain a latitude to associate
> with each watershed. Perhaps the center.
> lat.standard_name = "latitude";
> lat.units = "degrees_north";
> lat.bounds = "watershed_lats";
>
> float watershed_lons(cell, npoly_verts); // This variable will have
> the bounding longitudes for each watershed.
> watershed_lons._FillValue = -999.0; // Use this value for unused
> elements.
>
> float watershed_lats(cell, npoly_verts); // This variable will have
> the bounding latitudes for each watershed.
> watershed_lats._FillValue = -999.0; // Use this value for unused
> elements.
>
> float watershed_areas(cell); // This variable will have the area for
> each watershed.
> watershed_areas.standard_name = "area";
> watershed_areas.units = "km2";
>
> I have left lots of attributes out. I hope this helps.
>
> Grace and peace,
>
> Jim
> On 9/19/14, 4:09 PM, Signell, Richard wrote:
>
> Folks,
> A colleague asked me if a time series of data associated with a
> polygonal region (e.g. rainfall in a watershed) could be represented
> in CF.
>
> So two questions:
>
> 1. Any reason this could be represented as a simple time series with a
> cell_bounds = lon_verts, lat_verts
> lon_verts(npoly_verts), lat_verts(npoly_verts)
>
> 2. I see an approved ticket from 4 years agohttps://cf-pcmdi.llnl.gov/trac/ticket/64
> with "editorial correction" changing cell_bounds to bounds.
> Does that mean that CF1.6 we use "cell_bounds" but in CF1.7 we will
> use "bounds"?
>
>
> --
> [image: CICS-NC] <http://www.cicsnc.org/> Visit us on
> Facebook <http://www.facebook.com/cicsnc> *Jim Biard*
> *Research Scholar*
> Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/>
> North Carolina State University <http://ncsu.edu/>
> NOAA's National Climatic Data Center <http://ncdc.noaa.gov/>
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>
>
--
Dr. Richard P. Signell (508) 457-2229
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Woods Hole, MA 02543-1598
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Received on Fri Sep 19 2014 - 15:43:06 BST
