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Re: [netcdfgroup] Netcdf 4 examples

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  • Subject: Re: [netcdfgroup] Netcdf 4 examples
  • Date: Fri, 28 Dec 2007 12:44:52 -0700
Roy Mendelssohn <address@hidden> writes:

> Thanks Russ!  The first link in particular is the type of information
> we are looking for.  There are now quite a few ways to represent he
> same types of data, but it would be nice if there were consistent
> ways for doing so, plus some of the ways will be more efficient in
> terms of access, compression, ability to use chunking etc. etc.
>
> Also, based on the python interface that Jeff Whitaker wrote and his
> test programs  (while the calls are in python the bulk of the dirty
> work is done by the C libs), read access to a file using compression
> on a large array was roughly 8-10 times slower than the same array
> uncompressed, and the savings in size was roughly one order of
> magnitude.  Does this sound like what you would expect?  The
> compression feature is very attractive given the size of our files,
> but that is a reasonably large speed hit.

Yes, this sounds correct.

I am working on documenting this a bit more and then asking the HDF5
programmers if this is a bug or expected.

Certainly I expected compressed data to read faster, I am not seeing
that result.

Thanks,

Ed
--
Ed Hartnett  -- address@hidden