hdf-4.2r1 and netcdf-3.6.0p1

[Anthony M. Agelastos]

Hello all,

I recently tried to install a bunch of scientific software. Two such  
packages are opendx and grace (you can tell that I like data  
visualization). In any event, opendx has hdf as a dependency and  
grace has netcdf as one. After installing opendx, I tried installing  
grace and I get the message that

netcdf-3.6.0p1 conflicts with installed package(s):
hdf-4.2r1

They install files into the same place.
Please remove them first with pkg_delete(1).

Why do they install files into the same place and what can be done so  
that they can coexist on the same machine (without any problems)?  
Thank you for your assistance.

-Anthony