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[THREDDS #ZJS-544611]: On-the-fly unit-conversion in TDS

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  • Subject: [THREDDS #ZJS-544611]: On-the-fly unit-conversion in TDS
  • Date: Tue, 10 Aug 2010 11:31:37 -0600
Hi Greg,

The focus of the THREDDS Data Server (TDS) is providing access to data through 
various subsetting protocols. We do not support remapping/regridding or unit 
conversions. Instead we generally leave that to the client-side applications.

Of the four main protocols we support (OPeNDAP, NCSS, OGC WCS & WMS), only WCS 
and WMS have mechanisms that allow for remapping/regridding the data. None of 
them currently support unit conversion.

You might look into the Ferret-TDS, a server supported by another group which 
uses the TDS code with the Ferret analysis package. It allows OPeNDAP requests 
to dynamically generate datasets using server-side analysis. I believe Ferret 
supports unit conversion. The Ferret-TDS web page is

http://ferret.pmel.noaa.gov/LAS/documentation/the-ferret-thredds-data-server-f-tds/

Hope that helps,

Ethan

> Although support exists in the Unidata UDUNITS package, I cannot see any
> interface in the THREDDS data server that supports on-the-fly
> unit-conversions during data-requests.
> 
> With most conventions (and CDM), metadata for each dataset/field's units
> are clearly defined, and via UDUNITS it's possible to test whether a
> conversion (to the user's requested units) is possible.
> 
> Could you please direct me to the functionality I'm looking for (if it
> exists in the latest TDS 4.1 or 4.2)?
> 
> Alternatively, where do you think the best place to support
> unit-conversions would be (in the latest THREDDS codebase) and how
> extensive would you expect the changes required?
> 
> Thanks.
> Greg.


Ticket Details
===================
Ticket ID: ZJS-544611
Department: Support THREDDS
Priority: Normal
Status: Closed