Serving remote NCEP ETA fields via LAS

[Matt Howard <mkhoward@xxxxxxxx>]

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 |
+----------------------------------------------------------------------+