[Fwd: [Fwd: Serving remote NCEP ETA fields via LAS]]

[Matt Howard <mkhoward@xxxxxxxx>]

Hi Joe,

Actually there wasn't anything in my .dods_cache directory. However, I did
set permissions so all can write in that directory, and I quit and restarted
my browser (Netscape) and now it works.  So THANKS!

Matt

Joe McLean wrote:
> 
> Hi Matt,
> 
> I just tested the data configuration and it works fine for me.  In some of your tests, I think
> your DODS cache may have been corrupted.  Try clearing out your DODS cache directory.  In LAS
> v6.2 the directory is located at las/server/dods/.dods_cache.
> 
> Joe
> ----------------------------------
> 
> Matt Howard wrote:
> 
> > Dear Joe,
> >
> > Thanks for the suggestion, however it fails in LAS with the following error.
> >
> >  The following error message was received from LAS:
> >
> > Adding an acceptable error string: "*** NOTE: ".
> >         NOAA/PMEL TMAP
> >         FERRET v5.53
> >         IRIX 6.5 - 10/06/03
> >          4-Mar-04 11:50
> >
> > yes? cancel mode verify
> > yes? cancel mode interp
> > yes? canc data/all
> > yes? go std_initialize
> > "http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z"; "1"
> > "1" "vgrd10m"
> >  ** netCDF error: Invalid Argument
> >  is this a CDF file ?
> > set data
> > "http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z";
> > Command file, command group, or REPEAT execution aborted
> >
> > Help,
> >
> > Matt
> > -------------------------------------------------------------------
> >
> > Joe McLean wrote:
> > >
> > > Hi Matt,
> > > The url syntax for the LAS XML dataset configuration  is as follows.
> > > under the dataset element
> > > url="http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z";
> > >
> > > under the variable element
> > > url="http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z";
> > >
> > > or
> > > url="http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z#vgrd10m";
> > >
> > >
> > >
> > > The url under the dataset element does not need a variable specific syntax
> > > and, in fact, LAS will not know how to process the # syntax.
> > > LAS associates the dataset URL with the variable requested and uses the
> > > element tag ('vgrd10m') as the variable to access.  When a 'virtual dataset'
> > > is incorporated into LAS, different variable elements under the same dataset
> > > element may have different URL's. In these cases the URL under the variable
> > > element over-rides the dataset URL.   Either the variable element tag
> > > (vgrd10m) is used to access the data or the var_name in #var_name when the #
> > > syntax is iuncluded.
> > >
> > > I think what you want to use is the simplest form:
> > >
> > > <!-- Define datasets/variables -->
> > >    <datasets>
> > >     <eta12 name="Eta-12 V winds at 10m"
> > >
> > > url="http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z";>
> > >
> > >      <variables>
> > >       <vgrd10m name="North winds at 10m" units="Meters/sec">
> > >        <link match="/lasdata/grids/eta12_grid"/>
> > >       </vgrd10m>
> > >      </variables>
> > >      </eta12>
> > >    </datasets>
> > >
> > >
> > > Joe
> > > ------------------------------------------
> > >
> > > Matt Howard wrote:
> > >
> > > > Hi all,
> > > >
> > > > I'd like to access and serve NCEP ETA-12 numerical weather model forecast
> > > > fields.
> > > >
> > > > ( These fields are updated frequently, and the file name is based on the
> > > > date.
> > > >   So if you are reading this in the near future you may need to modify the
> > > >   urls given below to point to current output and follow along. So below
> > > >   eta20040304 is etaYYYYMMDD and you may have to use a current YYYY,MM,DD
> > > >   to point to an existing file if you want to follow along with this
> > > > question.)
> > > >
> > > > Here is a url to the output. These fields are served using a GDS at NCEP.
> > > > http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304
> > > >
> > > > I'd like to serve the hourly fields (eta1hr_00z).  You may see that there
> > > > are
> > > > many parameters inside this data set. One in particular is vgrd10m which is
> > > > North-South winds at 10m altitude.
> > > >
> > > > I really only want a regional subset - but for now I'll take all of the
> > > > values
> > > > on the [1:500][1:700] grid at 37 different hours.
> > > >
> > > > My question centers on how to properly specify the single parameter vgrd10m.
> > > >
> > > > The # on the url line is used in some examples, while a ? is sometimes used
> > > > in other examples of DODS urls. Neither works by the way.
> > > >
> > > > Ferret seems happy with using the following (with a ? in the constraint).
> > > >
> > > > "http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z?vgrd10m";
> > > >
> > > > But LAS complains asking "is this a cdf" file. I think the ETA fields start
> > > > out
> > > > as GRIB files which is something at GrADS-DODS Server is able to serve.
> > > >
> > > > Anyway, here is the xml fragment that I include in las.xml.  The interface
> > > > builds
> > > > ok but LAS isn't happy.
> > > >
> > > > I appreciate any help or insite you may have.
> > > >
> > > > <!-- Define datasets/variables -->
> > > >    <datasets>
> > > >     <eta12 name="Eta-12 V winds at 10m"
> > > > url="http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z#vgrd10m";>
> > > >
> > > >      <variables>
> > > >       <vgrd10m name="North winds at 10m" units="Meters/sec">
> > > >        <link match="/lasdata/grids/eta12_grid"/>
> > > >       </vgrd10m>
> > > >      </variables>
> > > >      </eta12>
> > > >    </datasets>
> > > > <!-- Define grids -->
> > > >    <grids>
> > > >     <eta12_grid>
> > > >      <link match="/lasdata/axes/eta12_x"/>
> > > >      <link match="/lasdata/axes/eta12_y"/>
> > > >      <link match="/lasdata/axes/eta12_t"/>
> > > >     </eta12_grid>
> > > >    </grids>
> > > > <!-- Define axes -->
> > > >    <axes>
> > > >     <eta12_x type="x" units="degrees_east">
> > > >      <arange start="-140.0" step="0.11" size="700"/>
> > > >     </eta12_x>
> > > >     <eta12_y type="y" units="degrees_north">
> > > >      <arange start="12.0" step="0.11" size="500"/>
> > > >     </eta12_y>
> > > >     <eta12_t type="t" units="hour">
> > > >      <arange start="2004-03-04 00:00:00" step="1" size="37"/>
> > > >     </eta12_t>
> > > >    </axes>
> > > > +----------------------------------------------------------------------+
> > > > | Dr. Matthew K. Howard                   Voice: (979)-862-4169        |
> > > > | Department of Oceanography                FAX: (979)-847-8879        |
> > > > | Texas A&M University              Internet: mkhoward@tamu.edu        |
> > > > | College Station, TX 77843-3146      webcam: http://seawater.tamu.edu |
> > > > +----------------------------------------------------------------------+
> >
> > --
> > +----------------------------------------------------------------------+
> > | Dr. Matthew K. Howard                   Voice: (979)-862-4169        |
> > | Department of Oceanography                FAX: (979)-847-8879        |
> > | Texas A&M University              Internet: mkhoward@tamu.edu        |
> > | College Station, TX 77843-3146      webcam: http://seawater.tamu.edu |
> > +----------------------------------------------------------------------+

-- 
+----------------------------------------------------------------------+
| Dr. Matthew K. Howard                   Voice: (979)-862-4169        |
| Department of Oceanography                FAX: (979)-847-8879        |
| Texas A&M University              Internet: mkhoward@tamu.edu        |
| College Station, TX 77843-3146      webcam: http://seawater.tamu.edu |
+----------------------------------------------------------------------+