label is the value of the attribute named "long_name" and that the value returned by coordsys is the value of the attribute named "cordsys".This was done in order to provide HDF with the ability to read netCDF files. While this aspect of HDF functionality will not affect its ability to read HDF data files written by programs compiled with earlier versions of HDF, it is advisable for HDF users to know this to be aware of the significance of the "long_name" and "cordsys" attribute names in a list of attributes.
To maintain backward compatibility with older versions of HDF, the RIS8 interface supported by HDF version 4.1 and later recognizes raster images stored using either set of HDF tags. Details on the different tags and structures used to store raster images can be found in the HDF Specifications and Developer's Guide v3.2 from the HDF WWW home page at http://hdf.ncsa.uiuc.edu/.