Hi Roy, Roberto:
Yes, we see the problem and will get a fix for it, thanks!
John
On 11/27/2011 8:13 PM, Roy Mendelssohn wrote:
Hi All:
This came up in the pydap mail list. I am quoting Roberto here:
Sorry, but the fact that it works with some clients doesn't mean it's working
as intended. In that dataset there are two different ways to retrieve the time
axis:
(1)
http://thredds1.pfeg.noaa.gov/thredds/dodsC/satellite/GR/ssta/1day.dds?analysed_sst.time
(2) http://thredds1.pfeg.noaa.gov/thredds/dodsC/satellite/GR/ssta/1day.dds?time
If you check the DDS responses above, you'll see that the two are identical. This is because
"time" is a map in the "analysed_sst" grid, but also a variable in the root
dataset, as we can see from the unconstrained DDS:
http://thredds1.pfeg.noaa.gov/thredds/dodsC/satellite/GR/ssta/1day.dds
Now, if you replace the ".dds" extension in the two requests above with ".dods", you'll
notice that the first one returns a "Request Too Big" error, while the second one is fine. My guess
is that there's a bug in the code that estimates the size of the requests.
Why does this work with other clients? As far as I know, pydap is the only
opendap client that does requests for the grid map (request #1 above), instead
of requests for the root variable (#2). Other clients that I've seen prefer the
second approach. I use the first one because... well, guess because I'm a
purist who sometimes favors purism over practicality*. :-P
I can confirm what he reports here (it actually started with an email from Chris Mueller
who was getting the reported "Request too big" error on some datasets even
though he was making small requests using the pydap client code. If you use the html
page or ERDDAP or toolsUI it works, but it fails with pydap for the reason given. I
believe Roberto is correct here that you should be able to query the grid map, which
means there is an error of some sort.
-Roy
**********************
"The contents of this message do not reflect any position of the U.S. Government or
NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
1352 Lighthouse Avenue
Pacific Grove, CA 93950-2097
e-mail: Roy.Mendelssohn@xxxxxxxx (Note new e-mail address)
voice: (831)-648-9029
fax: (831)-648-8440
www: http://www.pfeg.noaa.gov/
"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"
"the arc of the moral universe is long, but it bends toward justice" -MLK Jr.
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