Accessing TDS 4.3 and the new GRIB Feature Collections


Many changes have been made in the way GRIB files are handled in TDS 4.3; these changes will affect all TDS servers running 4.3. While the updates required to access resources on servers running the latest version of TDS, the new capabilities afforded by version 4.3 make the effort well worth it. To reiterate some of these changes:

Important notes:


GRIB Variable name changes:

The method in which GRIB 1/2 variable names are generated by the CDM has changed. This is to ensure the generation of unique, human readable variable names, without relying on the names contained inside the generally volatile GRIB tables. In order to aid in the transition, we have created a GribVariableRenamer class that will, when possible, return a unique GRIB variable name based on the old GRIB name. In some cases, such as mixed interval GRIB variables, a list of potential new variable names are returned. The class has command line functionality, and is accessed like this:

	java -Xmx1g -classpath ./netcdfAll-4.3.jar ucar.nc2.grib.GribConverterUtility -grib1|-grib2 <file> <oldVariableName> [-matchNCEP]

Note that is reliable only for for the NCEP GRIB files served on the Unidata TDS. Other datasets should be examined closely to determine how the variable has been renamed.


Access URL Updates:

Old URL New URL
http://motherlode.ucar.edu/thredds/catalog.xml http://thredds.ucar.edu/thredds/catalog.xml
http://motherlode.ucar.edu:8080/thredds/catalog.xml http://thredds.ucar.edu/thredds/catalog.xml
http://motherlode.ucar.edu:8081/thredds/catalog.xml http://thredds-test.ucar.edu/thredds/catalog.xml
http://motherlode.ucar.edu:9080/thredds/catalog.xml http://thredds-dev.ucar.edu/thredds/catalog.xml

Notes:

Also, the dataset UrlPaths on the Unidata TDS server have changed. While most of these changes are minor (for example, the removal of /frmc/ for /grib/ in the URL to indicate the collection type), not all changes are straight forward (especially for Best Time Series). In order to aid developers, we are providing an xml document that contains a mapping of old urlPaths to newUrl paths. This is the same xml file that the Unidata Integrated Data Viewer is using to help aid users in transition from TDS 4.2 to TDS 4.3.


This document is maintained by Sean Arms and was last updated December 2012