1. Using a Friendly OPeNDAP Client Library to Access HDF5 Data MuQun Yang and Hyo-Kyung Lee (The HDF Group) 1 25th IIPS Conference01/14/2009

2. OPeNDAP Review A software framework that allows simple access to remote data Data Access Protocol Client-server model Widely used by Earth Science Community 2 25th IIPS Conference01/14/2009

3. Client Library (libnc-dap) DAP Protocol (via http) Server (apache) Handler (hdf4_handler) Remote Data (HDF4) View Data (User) OPeNDAP Concept 3 25th IIPS Conference01/14/2009 Visualization Tools (gradsdap) Typical Remote Access FTP/HTTP Visualization tools (e.g. grads)

4. DAP Protocol (via http) Server (apache) Remote HDF5View Data (User) OPeNDAP HDF5 Handler 4 25th IIPS Conference01/14/2009 HDF5 Handler

5. DAP Protocol (via http) Server (apache) View Data (User) OPeNDAP HDF5 Handler with HDF-EOS5 5 25th IIPS Conference01/14/2009 HDF5 Handler Remote HDF5 Client Library (libnc-dap) Visualization tools (grads) Remote HDF-EOS5

6. HDF5 Handler DAP Protocol (via http) Server (apache) View Data (User) OPeNDAP HDF5 Handler with HDF-EOS5 6 25th IIPS Conference01/14/2009 HDF5 Handler w/ CF options Remote HDF5 Client Library (libnc-dap) Visualization tools (grads) Remote HDF-EOS5

7. Day After Server Tweaks Finally, Happy Clients! 7 25th IIPS Conference01/14/2009

8. HDF5-Friendly OPeNDAP Client Library 8 25th IIPS Conference01/14/2009 DAP Protocol (via http) Server (apache) View Data (User) HDF5 Handler Client Library (libnc-dap) Visualization tools (grads) Remote HDF5 HDF5 Handler w/ CF options HDF5-Friendly Client Library (liboc-dap) HDF5 GroupsView Groups???

9. Example: Groups in HDF5 Traditional OPeNDAP client library: It’s an attribute that I don’t understand. I’ll ignore it. HDF5-Friendly OPeNDAP client library: I was waiting for this key attribute to re-construct HDF5 9 25th IIPS Conference01/14/2009

10. Example: Reference in HDF5 Important for NPOESS Object / Regional Reference Map to DAP URL 10 25th IIPS Conference01/14/2009

11. One more reason: Help Clients to view Swath Our Client Library(prototype)

12. HDF5 Handler DAP Protocol (via http) Server (apache) View Data (User) Visualizing HDF-EOS5 Grids 12 25th IIPS Conference01/14/2009 HDF5 Handler w/ CF option Remote HDF5 Client Library (libnc-dap) Visualization tools (grads) Remote HDF-EOS5 Swath Visualizing HDF-EOS5 Swath Problem ??? HDF5-Friendly Client Library (liboc-dap) Visualization Tools (gradsoc) View Swath

13. Demo: MLS swath via GrADS 01/14/200925th IIPS Conference 13 CO at these elevations is a measure of pollution lower stratosphere upper stratosphere Before After During CO level near Beijing, China before, during and after Olympics

14. Summary HDF5 Access via OPeNDAP Is easy Is used by NASA GES DISC to serve Aura files HDF5-Friendly OPeNDAP Client Library Is a prototype Serves HDF5 better(EOS swath) Benefits visualization clients 14 25th IIPS Conference01/14/2009

15. Credits Mike Folk (The HDF Group) Robert McGrath (NCSA) Peter Leonard, Daniel Kahn, Marghi Hopkins (ADNET) Christopher Lynnes, James Johnson, Denis Nadeau, Fan Fang (NASA) Jennifer Adams (GrADS) Dave Brown (UCAR) 15 25th IIPS Conference01/14/2009

16. Acknowledgement This work was supported basing upon the Cooperative Agreement with the National Aeronautics and Space Administration (NASA) under NASA grant NNX06AC83A, NNX08A077A and NNX06AG75A. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of NASA. 16 25th IIPS Conference01/14/2009