Re: LAS access to NetCDF on a DODS server

[Cyndy Chandler <cchandler@xxxxxxxx>]

Ben,

see answers to your questions inline below ...


benb wrote:

Hello All,

I have installed a LAS system where all of the data is accessed from a datab
ase.  Now I want to use the basic (original) LAS capability which is accessi
ng NetCDF files.
  

you've done the more difficult type of installation already - rest should be easy by comparison!

The basic installation of LAS has 2 sample files (coads_climatology.nc and l
evitu_climatology.nc).  The XML files for generating the LAS menus include:
<COADS-climatology 
   name="COADS monthly climatology" 
   url="" class="moz-txt-link-rfc2396E" href="">"file:coads_climatology.nc" 

This apparently tells LAS that the coads_climatology.nc file is a local file
 (in the default Ferret data directory).  

correct.

How do I change this to tell the s
ystem that the file is on a DODS server?  For example:
<COADS-climatology 
   name="COADS monthly climatology" 
   url="" class="moz-txt-link-rfc2396E" href="">"http://DODS server address.directory a.directory b.coads_climatology
nc" 
  

Change the XML configuration file to look like this ...
<datasets>
     
     <coads_climatology_cdf
        name="COADS Climatology"
        url="" class="moz-txt-link-rfc2396E" href="">"http://DODServer.domain.name/dods-bin/nph-dods/$FER_DATA/coads_climatology.cdf"
        doc="doc/coads_climatology.html">

if you don't know it, the value of $FER_DATA can be determined by:
echo $FER_DATA
or by checking your ferret_paths script (often /usr/local/bin/ferret_paths)
and find the path that points to the file of interest

for example on my LAS installation, the COADS Climatology could be accessed by URI:
url="" class="moz-txt-link-rfc2396E" href="">"http://usjgofs.whoi.edu/dods-bin/nph-dods/data/smp/fer_dsets/data/coads_climatology.cdf"

Also, can anyone give me the URL (i.e. the correct content of url="" class="moz-txt-link-rfc2396E" href="">"http://DO
DS server address.directorya.directorb.coads_climatology.nc") for an example
 of a COARDS compliant NetCDF file on a DODS server that my system can acces
s for testing purposes?
  

Much (but not all) of the US JGOFS data collection is COARDS compliant NetCDF data. (The in situ Data Synthesis products are accessed from a database of JGOFS format profile data, not NetCDF).  You are welcome to access any of these files via the US JGOFS installation of LAS or via US JGOFS DODS.  Let me know if you have trouble determining appropriate URL syntax for any of them.

US JGOFS LAS
http://usjgofs.whoi.edu/las/servlets/dataset

a relatively small NetCDF dataset, which makes a good test case is:
Datasets > Synthesis Projects > Najjar monthly nutrients

and all the DODS served dataset URIs can be found by following each datasets blue info icon and selecting the DODS info link,
ie. the Najjar monthly nutrients via DODS would be:
http://usjgofs.whoi.edu/dods-bin/nph-dods/data/smp/najjar/Najjar.nc.info
and in the LAS xml config file this looks like:
url="" class="moz-txt-link-rfc2396E" href="">"http://usjgofs.whoi.edu/dods-bin/nph-dods/data/smp/najjar/Najjar.nc"

I'm especially concerned that the "Compare Two" function will work with thes
e NetCDF files.  Can you tell me if Compare Two will work if coads_climatolo
gy.nc is being accessed from a DODS server?
  

The 'Compare Two' function will work for DODS served datasets.
Try pointing your LAS to the coads_climatology.cdf file served via US JGOFS DODS
url="" class="moz-txt-link-rfc2396E" href="">"http://usjgofs.whoi.edu/dods-bin/nph-dods/data/smp/fer_dsets/data/coads_climatology.cdf"

Hope this is an easy one to answer.  Thanks in advance for your help.
  

Hope this reponse has been helpful.  Good luck!


Cheers,  Cyndy

Ben


  

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Cyndy Chandler		| voice: (508) 289-2765
MS #43, WHOI		| Office hrs: M-F ~ 9-4
Woods Hole, MA  02543	| FAX: (508) 457-2161
cchandler@whoi.edu | http://www.whoi.edu/people/cchandler
U.S. JGOFS Data Management Office
Department of Marine Chemistry and Geochemistry
Woods Hole Oceanographic Institution