1/14/200925th IIPS Conference 1 Challenges to Archive and Access NASA HDF-EOS Data in the long Term MuQun Yang (The HDF Group) Choonghwan Lee (The HDF Group) Ruth Duerr (NSIDC )

Prerequisite METS(Metadata Encoding & Transmission Standard) Standard for encoding structural metadata ISO International Schema for describing geographic information File-level Metadata Metadata about the individual file or granule Dataset-level Metadata Metadata that applies to each and every granule/file in the whole data set(product) 1/14/200925th IIPS Conference 2

1/14/200925th IIPS Conference 3 HDF5 Archive Information Package Data file HDF5 METS Primary Schema Extension Schema | | | |-- | |-- | HDF5 AIP Components Metadata file

1/14/ th IIPS Conference 44 NOAA SDS Program NetCDF4/HDF5-data NetCDF4 / HDF5 Data METS NSIDC/ ECS HDF4-data NCDC:CLASS ISO HDF5-AIP H4to H5 ECS to ISO NSIDC/ECS Metadata ECS Users CDM/NetCDF4 ECS to METS

Enhanced H4toH5 conversion tool Convert HDF-EOS2 data to NetCDF4-compliant HDF5 data Official release (2.0) can be found at 1/14/200925th IIPS Conference 5 $./h4toh5 –eos –nc4 input.he2 output.nc4

Challenges to do the conversion Retrieve geo-location information from HDF- EOS2 data Conform to NetCDF4 data model in the existing H4toH5 conversion tool …… 1/14/200925th IIPS Conference 6

Grid lacks geolocation fields Use predefined projections Geographic Sinusoidal Polar stereographic … New converter creates geolocation fields HDF-EOS2 API GDij2ll() 1/14/200925th IIPS Conference 7 Challenges: Handle EOS - Grid Data [4][12] Lon[12] Data [4][8] Lon[4][8] Geographic Sinusoidal

The size of geolocation fields can be different from data fields New converter has to handle geolocation fields correctly 1/14/200925th IIPS Conference 8 Challenges: Handle EOS - Swath

Follow CF conventions Create two variables: NewLongitude and NewLatitude Add to the data field an attribute coordinates=“NewLongitude NewLatitude” Keep the original Latitude and Longitude 1/14/200925th IIPS Conference 9 Challenges in conforming to NetCDF4 Data field has three columnsLongitude field has two columns New longitude has three columns

1/14/200925th IIPS Conference 10 Now some examples to show NetCDF4 files converted from EOS2

1/14/200925th IIPS Conference 11 A netCDF-4 file converted from EOS2 data at NSIDC

1/14/200925th IIPS Conference 12 A netCDF-4 file converted from EOS2 data at NSIDC

Deliverables and future work Deliverables 1.Enhanced HDF4 to HDF5 conversion tool 2.A validation tool to verify the correctness of the conversion Will be released soon! 1/14/200925th IIPS Conference 13

1/14/200925th IIPS Conference 14 Acknowledgement This work was supported under NOAA Scientific Stewardship Program grant number NA07OAR 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 NOAA.