I finally sat down to try and output to NetCDF from the Environmental
Fluid Dynamics Code (EFDC) that we use for estuarine modeling.
EFDC already handles all computation in a gather compression mode so
that would seem to be a good fit to have, plus only about 10% of the
cells are wet cells which would make a big impact on file size if I kept
the blank cells about.
EFDC uses a ordered, boundary-fitted, curvilinear, 4-sided cell grid
with sigma-stretched layers in the vertical. That is a mouthful.
We use UTM for the coordinates so the NetCDF needs to have projection
information.
It seems like I have tried everything and I can't get any NetCDF tool to
bring in this dataset. I have tried IDV, Panoply, ncview (doesn't
really support projection data), ncBrowse, and maybe some others.
IDV does the best, at least putting the projected coordinates near the
right spot in the 'Region' map, but IDV thinks that the WSElevation data
is (3013, 3013) instead of (259, 121).
I have 4 warnings when using the CF Compliance checker:
WARNING (7.1): Data for variable y lies outside cell boundaries
WARNING (7.1): Data for variable x lies outside cell boundaries
...
------------------
Checking variable: rgrid
------------------
WARNING (3): No standard_name or long_name attribute specified
WARNING (3.1): units attribute should be present
The first two I can fix because it must be related to the algorithm to
calculate the cell corners. I have checked the last few cells and they
are correct. The 'rgrid' variable is my gather compression variable and
it shouldn't have units, nor could I find a reasonable standard name.
Here is the CDL:
netcdf efdcout {
dimensions:
IC = 259 ;
JC = 121 ;
rgrid = 3013 ;
nv = 4 ;
time = UNLIMITED ; // (2 currently)
variables:
int transverse_mercator ;
transverse_mercator:grid_mapping_name =
"transverse_mercator" ;
transverse_mercator:latitude_of_projection_origin = 0. ;
transverse_mercator:longitude_of_central_meridian = -81. ;
transverse_mercator:false_easting = 500000. ;
transverse_mercator:false_northing = 0. ;
transverse_mercator:scale_factor_at_central_meridian =
0.9996 ;
int rgrid(rgrid) ;
rgrid:compress = "IC JC" ;
float WSElevation(time, rgrid) ;
WSElevation:standard_name =
"height_above_reference_ellipsoid" ;
WSElevation:units = "m" ;
WSElevation:coordinates = "x y" ;
WSElevation:grid_mapping = "transverse_mercator" ;
float x(rgrid) ;
x:standard_name = "projection_x_coordinate" ;
x:units = "m" ;
x:bounds = "x_bnds" ;
float y(rgrid) ;
y:standard_name = "projection_y_coordinate" ;
y:units = "m" ;
y:bounds = "y_bnds" ;
float x_bnds(rgrid, nv) ;
float y_bnds(rgrid, nv) ;
double time(time) ;
time:standard_name = "time" ;
time:units = "days since 1995-1-1 0:0:0" ;
// global attributes:
:Conventions = "CF-1.0" ;
}
Any ideas on what I am doing wrong?
Kindest regards,
Tim Cera
