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Re: common data models



Hi Brian:

Bryan Lawrence wrote:
hi John

Happy Wednesday and all that (seems a bit late for New Year).

I've just been catching up on my reading ...

I was looking at the papers you and Russ are presenting at AMS, and had a question about data models. ...

BTW, a recent ppt is here:

http://www.unidata.ucar.edu/staff/caron/presentations/CDM.ppt

a few diagrams in there you may be interested in.


Do you have UML for the relationship between the CDM and the NetCDF4 data model and aggregations ...

As it stands CDM == NetCDF4 data model

I guess what you're asking about is the relationship between CDM and 
aggregations ?

I dont have a UML about aggregations, im not sure they can be thought about in 
that way. (However I'll think about it and see if anything occurs).


(I figure I could construct one, but I'm trying to understand exactly what you guys have done ... in the context of aggregation and non netcdf files etc ... and it seems more sensible to ask you how your model works than get it wrong :-)


Part of my context of this is thinking about what to do with work we've done on supporting the met office pp format thru the cdunif library which forms part of PCMDI's CDAT. We (and the Met Office) need to think strategically and it's not obvious that we want to keep engineering inside cdunif (but it's not obvious we wouldn't either, as we're unlikely to do it in Java).

If its aggregations you need, then only Netcdf-Java can do that. You could aggregate through a TDS, then read the data through opendap.


Many moons ago a number of us thought about trying to bring all these I/O packages under one hood ... it seems to me like you've done that to some extent in your NetCDF-java library, but I need to understand the structure (without reading code :-)

Now here I guess youre talking about reading in different file formats? We call the the IOSP layer. Again, only in Java, but again could access through opendap.


This is by no means an urgent request for information :-)

im not sure if i answered your questions.


Best wishes Bryan

p.s. sorry we've been uncommunicative about access control and Thredds, it's not off my agenda ... just down further than I would like ...


yes, its on my TODO list, ill let you know if i get to it.


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