Rich,
As far as I can tell, the attribute name has always been 'bounds'. I
don't know if it was a find/replace error or what, but the CF
Conventions document uses 'cell_bounds' a couple of times in the body of
the text, even though every example in the document uses 'bounds'. This
is confusing, and should probably be changed.
Grace and peace,
Jim
On 9/19/14, 5:43 PM, Signell, Richard wrote:
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 <[email protected]
<mailto:[email protected]>> 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 ago
https://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"?
--
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/>
151 Patton Ave, Asheville, NC 28801
e: [email protected] <mailto:[email protected]>
o: +1 828 271 4900
--
Dr. Richard P. Signell (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
--
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/>
151 Patton Ave, Asheville, NC 28801
e: [email protected]
o: +1 828 271 4900
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