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[IDV #KOO-280301]: Reading data via URLs in IDV: setting Content-Length and Accept-Ranges headers

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  • Subject: [IDV #KOO-280301]: Reading data via URLs in IDV: setting Content-Length and Accept-Ranges headers
  • Date: Tue, 24 Jun 2008 09:26:10 -0600
Hi Dave:

MADIS data uses linked lists of records that is so slow when using remote 
access that its pretty much unuseable, although local access for not-too-huge 
datasets is ok.

We are working on a new service in the TDS for point data access in IDV, which 
does all the selection on the server for performance, but its still a few 
months away.

It appears you are using a simple HTTP server for your data. Your best bet at 
the moment is to copy it locally and access from there. Note that you will have 
to run a TDS server (when thats ready) to get reasonable remote access.

> 
> On Jun 12, 2008, at 2:40 PM, Unidata THREDDS Support wrote:
> 
> > Ah ha! I just got it to read in (your MADIS data that is, 
> > http://funnel.sfsu.edu/data/LDAD/urbanet/20080610_1200.nc)
> > . It worked when I selected "netCDF Point Data files" for the Data
> > Source Type (it took a long time because reading this kind of linked
> > list point data is not efficient over HTTP).
> 
> 
> Ethan,
> 
> Right--specifying data type "netCDF Point Data files" is necessary to
> get the data loaded and plotted, regardless of the access method.
> 
> I'm running IDV v2.5. On my machine, the IDV succeeds in loading the
> file you refer to above via both of my Web servers (funnel and virga),
> so we're producing the same result.
> 
> However, trying to load and plot another NetCDF file with a much
> larger set of data doesn't work. Try the same URL as above (either
> server) but change "urbanet" to "mesonet4". (These files are an order
> of magnitude larger, but are still NetCDF point data that I can load
> and plot when accessing the via the local file system but not via HTTP.)
> 
> -- Dave
> 
> 
> 
> 
> 
> 


Ticket Details
===================
Ticket ID: KOO-280301
Department: Support THREDDS
Priority: Normal
Status: Open