under the variable element
url=""http://nomad1.ncep.noaa.gov:9090/dods/eta/archive/eta20040304/eta1hr_00z">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">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">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/eta20040304I'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">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 |
+----------------------------------------------------------------------+