Hi Dennis,
> On Dec 4, 2014, at 12:48 PM, Dennis Heimbigner <dmh@xxxxxxxx> wrote:
>
> Is this the H5Pset_fapl_core procedure?
No, I was thinking of this feature set:
http://www.hdfgroup.org/HDF5/doc/Advanced/FileImageOperations/HDF5FileImageOperations.pdf
Quincey
> =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
>>
>> _______________________________________________
>> netcdfgroup mailing list
>> netcdfgroup@xxxxxxxxxxxxxxxx
>> For list information or to unsubscribe, visit:
>> http://www.unidata.ucar.edu/mailing_lists/
>>
>>
