Is this the H5Pset_fapl_core
procedure?
=Dennis
Quincey Koziol wrote:
> Hi all,
> The HDF5 library has a "file image" feature that allows a memory buffer
> to be opened as a "file". The netCDF-4 library could be extended to support
> this feature in HDF5.
>
> --
> Quincey Koziol, The HDF Group
> Full Contact Info: http://bit.ly/QuinceyKoziol
>
>> Hi Roy: It's not too big a deal, the netCDF 3 format is nicely
>> orthogonal and easy to parse. The attached perl library is only around
>> 350 lines long with adequate comments, but it gives you most basic
>> functionality you need for reading.
>>
>> Regards,
>>
>> Doug
>>
>> On 11/20/14 10:36, Roy Mendelssohn - NOAA Federal wrote:
>>> Hi Doug:
>>>
>>> Thanks for the comments. I would be interested on seeing the perl code,
>>> just to see how complicated it is to do this (though I don?t really know
>>> perl). Fro my purposes. since this is something we will be distributing,
>>> we want to keep what we do to code that is ?native? to the program, in
>>> this case R.
>>>
>>> -Roy
>>>
>>> On Nov 20, 2014, at 8:48 AM, Doug Hunt <dhunt@xxxxxxxx> wrote:
>>>
>>>> Hi Roy: I had a similar problem earlier this year. I wanted to open a
>>>> netCDF 3 file and read from it using the netCDF library when the file was
>>>> presented to me in memory instead of as a disk file.
>>>>
>>>> I spent some time examining the netCDF library source and talking to
>>>> UNIDATA folks about this and determined that the library was too hard to
>>>> change. The interface depended upon passing in a file name and it would
>>>> be too hard to modify it to add an 'ncopen' that took a pointer to memory
>>>> instead .
>>>>
>>>> What I ended up doing was writing a reader from scratch in perl (since
>>>> this application was in perl using the PDL::NetCDF interface) that reads
>>>> the raw netCDF3 binary format.
>>>>
>>>> This has proved to be a good lightweight solution for us, but it does
>>>> restrict us to netCDF 3.
>>>>
>>>> I'd be happy to share my perl netCDF 3 reader library if you are
>>>> interested.
>>>>
>>>> Incidentally, as a result of this experience, I came away with an
>>>> appreciation for the elegance and good design of the netCDF 3 binary
>>>> format and a suspicion of the netCDF 4 format as being too complex and
>>>> having too much library overhead.
>>>>
>>>> Regards,
>>>>
>>>> Doug
>>>>
>>>> On 11/19/14 18:41, Roy Mendelssohn - NOAA Federal wrote:
>>>>> Hi All:
>>>>>
>>>>> Netcdf now has the option of creating or reading a file entirely in
>>>>> memory, a nice option to have. I am wondering if there is any way to do
>>>>> sort of the inverse. Some web libraries allow for a pure binary download
>>>>> of a file into memory, so what I have sitting there is essentially a
>>>>> binary image of the netcdf file. Is there any way to open that image
>>>>> without writing to disk?
>>>>>
>>>>> As an example, the R httr library allows this. I can for example
>>>>> download to memory a netcdf file from ERDDAP, and if I then do a binary
>>>>> save in httr and then read it back in using the ncdf4 package, it all
>>>>> works great. But it would be even better if I could skip the extra
>>>>> steps, and ?open? the image in ncdf4 directly (ncdf4 btw can do whatever
>>>>> the netcdf libraries can do, so it is a question of the base libraries).
>>>>>
>>>>> Thanks,
>>>>>
>>>>> -Roy
>
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