A new version of the netCDF-Java library (4.3.16) is included in this
release. This version of netCDF-Java includes major changes to the way GRIB 1
and 2 files are handled. See
netCDF-Java GRIB documentation for a more details on these changes.
One major outcome of this change is that GRIB variable names will now be
generated in a very general way. This means that bundles that were generated
with a previous version of the IDV might break. In order to aid users in the
transition between netCDF-Java 4.2 and 4.3, the netCDF-Java library has provided
a mapping of old variable names and new variable names for the datasets served
on the Unidata THREDDS Data Server (TDS), and this mapping is being used 'under
the hood' in the IDV to minimize the impact of these changes on users.
For users reading GRIB files from other locations (local files or other remote
servers), the IDV now allows users to make custom variable name mappings. New
variable mappings should be placed in the following file (found under the users
The structure of this file is quite simple:
Changes to the way GRIB files are served via the Unidata TDS server have also
been made. The impact of this change on IDV users is that the dataset URLs that
point to GRIB resources will change, which will break bundles that point to the
old Unidata TDS (motherlode.ucar.edu).
Again, in order to aid users in this transition, the netCDF-Java library has
provided a mapping between the old and new dataset URL paths for all datasets
served through the Unidata TDS. As with the variable name changes, the URL
mapping for datasets on the Unidata TDS is being used 'under the hood' in the
IDV to minimize the impact on users.
The latest version of TDS (4.3), where URL related impacts will be
seen, is now running on the main Unidata TDS (thredds.ucar.edu).
Starting with this release (4.0u1), the IDV will redirect all requests to the old
Unidata TDS (motherlode.ucar.edu) to the new Unidata TDS (thredds.ucar.edu)
automatically and update the appropriate data URLs. Unlike the previous
release (4.0), users do not need to install any plugins related to the
TDS upgrade. If you previously installed plugins related to the TDS
upgrade, please remove them once you've upgraded to IDV 4.0u1 (or later).
As TDS servers in the community begin to upgrade to TDS 4.3, IDV users will
likely need to use custom URL mappings. New URL mappings should be placed in the
following file (found under the users home directory):
Again, the format of this file is quite simple:
In the first example, a new THREDDS server has replaced an old server - all
requests going to oldthreddsserver1.edu will be directed to
newthreddsserver1.edu. The second example is where the URL path to a particular
dataset has changed, either because the product has been replaced (for example,
the RUC to the RAP transition) or the maintainer of the TDS server has changed
the way data are cataloged. Note in both cases the type of URL is an opendap
URL. In the future, this mechanism will be used to redirect other types of data
requests, such as ADDE requests.