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

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  • 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:


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


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:


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