Re: netcdf and HDF Explorer

Hi Pedro,

> In last Friday's telecom meeting I forgot to tell that I did a HDF
> reader called HDF Explorer
> 
> you can download it here
> 
> http://www.space-research.pt/
> 
> I find it very convenient to quickly analyze HDF5 and HDF files on
> Windows, where I do development.  there is also a non downloadable
> version of the of the program (it generates images from datasets)
> and it is a commercial version but I 'll be happy to send you a CD.
> 
> I had the idea of making the program to read netcdf files.  I did
> some tests on including the version 3 of netcdf in HDF Explorer, but
> there are problems with this, since HDF has a built in 2.4 netcdf
> version , and conficts arise (compiler and linking errors).  did you
> ever tried to link an application with both the 2.4 and v3 libraries
> ?

Yes, by default the default netCDF 3 library includes an
implementation of the 2.4 interfaces for backward-compatibility, so
having two of those is causing the problem.  If you build netCDF
3.5.1-beta with the -DNO_NETCDF_2 flag, it is supposed to omit support
for the 2.x interfaces, and this might allow linking.

> however, by a quick look at the manual of v3 , I think I can use the
> v2.4 interface to read the current v3 files . Is that correct ?

Yes, those version numbers just refer to different language interface,
not to different formats.  There has never been more than one version
of the netCDF format, which is still version 1.  This tends to cause
confusion, so we sometimes just refer to "netCDF-3 format" (really
version 1) and "netCDF-4 format" (a tailored HDF5 format).

> looking at the object model of netcdf (which I believe is almost
> identical of HDF SDSs) and at the code of the ncdump, I think it
> would be very easy to include netcdf with HDF Explorer, since HDF
> Explorer has a object model that is ready to read and display
> different file formats (HDF and HDF5).
> 
> I did not find a version 2.4 on the website. is there one available
> somewhere ?

Yes:

  ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-2.4.3.tar.Z

--Russ