[thredds] NetCDF Subset Service: can't get value of variables of certain dimensions

• To: THREDDS Users <thredds@xxxxxxxxxxxxxxxx>
• Subject: [thredds] NetCDF Subset Service: can't get value of variables of certain dimensions
• From: John Maurer <jmaurer@xxxxxxxxxx>
• Date: Fri, 09 Sep 2011 14:43:14 -1000

Hi All,
One of our ocean forecasts has variables of differing dimensions. Though
most vary in space, time, and depth, for some reason I cannot grab the value
of a variable that only varies in space using NetCDF Subset Service (NCSS).
Ideas?, a bug?

I'm trying to grab the bathymetry value (variable "h") in meters at a
specific grid point in order to compute depth using the formula for the
ocean_s_coordinate_g2 sigma coordinate, which includes s_rho, Cs_r, zeta, h,
and hc.

Here's the NetCDF Subset Service "as a point dataset" page for one of our
ROMS catalogs:

http://oos.soest.hawaii.edu/thredds/ncss/grid/hioos/roms_forec/hiig/ROMS_Hawaii_Regional_Ocean_Model_best.ncd/dataset.html

When I attempt to pull the "h" variable I get no results. Here's an example:

http://oos.soest.hawaii.edu/thredds/ncss/grid/hioos/roms_forec/hiig/ROMS_Hawaii_Regional_Ocean_Model_best.ncd?var=h&latitude=20&longitude=-157&temporal=all&time_start=2011-03-25T00%3A00%3A00Z&time_end=2011-09-16T00%3A00%3A00Z&time=2011-03-25T00%3A00%3A00Z&vertCoord=&accept=csv&point=true

Since "h" does not have a time or depth axis, it shouldn't (in theory)
matter what I choose to enter in the time and vertical level fields.
However, I've tried many combinations with no luck. I can grab "zeta" fine
(sea surface height), which varies in space and time but not depth. If I try
to get "h" along with any other variable, "h" is reported as NaN. As a
sanity check to prove that there are "h" values in this dataset, you can
inspect our TDS catalog and try OPeNDAP:

http://oos.soest.hawaii.edu/thredds/catalog/hioos/roms_forec/hiig/catalog.html?dataset=roms_hiig_forecast/ROMS_Hawaii_Regional_Ocean_Model_best.ncd
http://oos.soest.hawaii.edu/thredds/dodsC/hioos/roms_forec/hiig/ROMS_Hawaii_Regional_Ocean_Model_best.ncd.ascii?h[0:1:193][0:1:293]

In case it matters, this dataset is on a curvilinear grid. Thanks for giving
this a look.
Cheers,
John Maurer
Pacific Islands Ocean Observing System (PacIOOS)
University of Hawaii at Manoa