NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.

To learn about what's going on, see About the Archive Site.

Re: 1.8 file format

NOTE: The netcdf-hdf mailing list is no longer active. The list archives are made available for historical reasons.


Hmm, looks like the docs are out of date and/or wrong for region references. Because region references are variable in length, the actual reference information is stored in the global heap and a (fixed length) heap ID is stored in the dataset's raw data - that part is right, although too briefly described.

the data storage layout messaage seems to imply the HeapID is 12 bytes long. 
Usually they are 16 bytes long.

   type = Layout(8); contiguous storageSize = (2,12) dataAddress=13352

I dont see enough detail in h5dump:

        DATASET "VIIRS-NCC-EDR_Gran_0" {
           DATATYPE  H5T_REFERENCE
           DATASPACE  SIMPLE { ( 2 ) / ( 2 ) }

is there another option that would verify that?

in any case is 12 bytes correct? if so, what does a 12-byte HeapId look like?

The format of the data in the
heap is wrong however. The information actually stored in the heap is as follows: - The offset of the object header of the object (ie. dataset) pointed to (yes, an object ID) - A serialized form of a dataspace _selection_ of elements (in the dataset pointed to). I don't have a formal description of this information now, but it's encoded in the H5S_<foo>_serialize() routines in src/H5S<foo>.c, where foo = {all, hyper, point, none}.

There is _no_ datatype information stored for these sort of selections currently.

I'll file a bug report in our bugzilla to make certain this description gets fixed in the file format spec.

    Quincey


==============================================================================
To unsubscribe netcdf-hdf, visit:
http://www.unidata.ucar.edu/mailing-list-delete-form.html
==============================================================================


  • 2007 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the netcdf-hdf archives: