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Re: Does TDS really synthesize CF curvilinear coordinates for GRIB data?
- Subject: Re: Does TDS really synthesize CF curvilinear coordinates for GRIB data?
- Date: Fri, 09 Apr 2010 11:44:01 -0600
are you asking this to be done on motherlode, or one of your servers?
we deliberately dont use 2D coordinates because of their size, and because the calculation can be done on the (our) client, which is more efficient.
what is your use case?
Steve Hankin wrote:
Hi John,
Yes -- this is the Motherlode TDS.
Looking at the first link as an example, it contains a variable,
"Polar_Stereographic", whose attributes describe the projection. There
are "grid_mapping" attributes that point to it for the relevant
dependent variables. So much of the CF compliance work has been done.
What remains is for the IOSP to
1. note that the grid_mapping machinery exists for a particular file
2. inspect the grid_mapping parameters
3. synthesize the latitude and longitude coordinate variables
4. fix up the "coordinates" attributes of the dependent variables so
that instead of pointing to
coordinates: "run time y x"
they point to
coordinates: "run time *my_synth_latitude my_synth_longitude*"
- Steve
=================
John Caron wrote:
Steve Hankin wrote:
Hi John,
At the NCDC meeting we talked about IOPS's for various binary data
formats. I *thought* I heard you say that the recent TDS IOSP for
GRIB data would automatically synthesize the CF curvilinear
coordinates. When I look at examples like the ones below on
Motherlode, I spot only coordinates in kilometers. (polar
stereographic and lambert conformal examples listed below)
Did I misunderstand something? What is your recommendation for
getting generating the curvilinear (CF) coordinate variables that we
need for the UAF project? We don't want to do it manually if it is
already a solved problem.
sorry to trouble you. I know you're busy - Steve
http://motherlode.ucar.edu:8080/thredds/dodsC/fmrc/NCEP/GFS/Alaska_191km/NCEP-GFS-Alaska_191km_fmrc.ncd.html
http://motherlode.ucar.edu:8080/thredds/dodsC/fmrc/NCEP/RUC2/CONUS_20km/surface/NCEP-RUC2-CONUS_20km-surface_best.ncd.html
we dont automatically generate the 2D coords, but we could. the main
issue would be to figure out how to tell the GRIB IOSP to do so, ie
configuration. Would this be a global setting, or per-dataset? I
assume this is coming through a TDS?