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We will introduce the fully functional HDF5-OPeNDAP data handler in this talk. The features we have added into the data handler includes …

We will introduce the fully functional HDF5-OPeNDAP data handler in this talk. The features we have added into the data handler includes

- Mapping Compound Datatype to DAP Structure
- Mapping EOS Grid to DAP Grid
- Partial Support of CF Conventions
- Comprehensive Testsuite

At the end, we will show demos of using an OPeNDAP client to read HDF-EOS5 Aura data.

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    No notes for slide
  • DAP use “.” as a delimiter to obtain a member of a struct.
    No corresponding datatype in DAP
    64-bit integer: Are there any uses for that?

Transcript

  • 1. Software to access HDF5 Datasets via OPeNDAP MuQun Yang, Hyo-Kyung Lee The HDF Group 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 1
  • 2. Previous work review HDF5-OPeNDAP server: • • • • Incomplete mapping from HDF5 to OPeNDAP No comprehensive test suite Only tested a few examples on two platforms Incomplete documentation HDF5-OPeNDAP client: • No client at all 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 2
  • 3. Previous HDF5OPeNDAP Support HDF5 DAP No Client 11/8/2007 Prototyped Server HDF and HDF-EOS Workshop XI, Landover, MD 3
  • 4. Proposed work First Year HDF5 server Clients: Matlab etc. DAP 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 4 HDF5
  • 5. Current Status HDF5 server Clients: Matlab etc. DAP 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 5 HDF5
  • 6. 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 6
  • 7. HDF5 Server Status – New Features • • • • 11/8/2007 Mapping Compound datatype to DAP Structure *Mapping EOS Grid to DAP Grid *Mapping HDF5 group to DAP *Mapping HDF5 object and regional references to DAP HDF and HDF-EOS Workshop XI, Landover, MD 7
  • 8. HDF5 Server Status - Test • • • • Code Cleanup – updating to the latest version of HDF5 Comprehensive testsuite – DejaGNU Internal Aura EOS file testsuite Inside OPeNDAP’s nightly build system DONE 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 8
  • 9. HDF5 Server Status – Special Support • • • • Partial Support of CF conventions Relative Object Path Support Configuration Options HDF5-OPeNDAP handler Website DONE 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 9
  • 10. HDF5 Server Status - Documentation • • • • Mapping HDF5 group to DAP -- Done! Limitations of HDF5-OPeNDAP handler – In progress! Mapping Object reference to DAP – In Progress! Experiments with OPeNDAP clients – In Progress! In Progress ! 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 10
  • 11. Using OPeNDAP Clients to serve HDF5 data • Matlab Client – in progress • Testing OPeNDAP Clients to read NASA HDF-EOS5 files  Ferret  ncBrowse  IDV  ODC  GrADS 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 11
  • 12. Several Highlights • HDF5-OPeNDAP Handler Website • Limitations of the current handler • Demo: Visualizing HDF-EOS5 Aura data with existing OPeNDAP clients • Limitations of the existing clients 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 12
  • 13. HDF5 OPeNDAP Website • URL: http://hdfdap.hdfgroup.uiuc.edu:8080/ 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 13
  • 14. Limitations of the handler • No support for HDF5 files that have a '.' inside a group/dataset name • No support for any variable length types except for 1 dimensional variable-length string array • No support for ENUM,BITFIELD,OPAQUE types • 64 bit integer (array) is not supported • Both signed and unsigned char map to Byte 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 14
  • 15. Demo • Ferret • NCBrowser • IDV 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 15
  • 16. Summary of accessing Aura L3G Data via OPeNDAP clients Client Problem Solution Notes N/A 2D display only. No way to latitude and longitude information. ncBrowse N/A Ferret Geolocation fields should fit Attributes with units map geolocation value to into longitude(-180~180) should be provided longitude and latitude and latitude (-90~90) range for correct display. IDV Strictly Follows CF convention. Need Short names(<15 characters for variables) and need units for attributes. GrADS Strictly Follows CF convention. Maybe 3D(x,y,time) Grids only? It entirely depends on Renaming grid map data libdap-nc client variables? library. ODC N/A N/A 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD Beautiful user interface. It can't display data. Data retrieval is OK. 16
  • 17. Second year Plan • High-level HDF5 client • Working with GrADS team • We really would like to hear feedbacks from Users Please send emails to ymuqun@hdfgroup.org hyoklee@hdfgroup.org 11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 17
  • 18. Acknowledgement This work was supported basing upon the Cooperative Agreement with the National Aeronautics and Space Administration (NASA) under NASA grant NNX06AC83A 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.  11/8/2007 HDF and HDF-EOS Workshop XI, Landover, MD 18