Status Report for Decoders September 30, 2009

Decoder Packages
Robb Kambic
Unidata Program Center
September 30, 2009

The Java Grib Libraries have been enhanced to have the complete Product Definition (PDS) and Grib Definition sections (GDS) included in the index. The benefit is that all the information is now available to the Common Data Model (CDM) layer and layers above it, ie the IDV. This change was needed to support the Ensemble type of data models of Short Range Ensemble Forecast(SREF) and Global 1.0 degree Ensemble (GEFS) IDD models as well as the African Initiative and TIGGE data. Also, the inclusion of the PDS and GDS sections as byte arrays made the size of the indexes smaller and eliminated the need to convert String data types to numeric data types, making the reading process of the index much faster.

Other changes to the library included:

  • changing the suffix of the index file to gbx8 so both older and new indexes can co-exists.
  • adding GribIndexName to manage which index to use
  • adding Sigma Vertical levels processing
  • implementing second Order Spatial Differencing code; truly implemented because there was a test file.
  • changing GDS Winds flag to VectorComponentFlag and elevated to the CDM layer for use in attributes for variables.
  • appending the error suffix is now appended to the variable names.