[gradsusr] * * * New Release of GrADS version 2.0.a8 * * *

[Jennifer Adams]

Dear All (on both lists):

I have posted a new version of GrADS: 2.0.a8. The GrADS downloads web  
page (http://iges.org/grads/downloads.html) has been updated with  
links to the source code and a few pre-compiled binaries. This release  
has many new features, including several that were required to support  
COLA's work with extremely high resolution data sets.

GrADS version 2.0.a8 is linked with netCDF-4, which supports  
compressed netCDF files and also has a new OPeNDAP interface for  
gridded data sets. This new version of the netCDF library makes it  
possible to have a single, fully-functional GrADS executable, named  
"grads". The support for reading and writing compressed netCDF is  
mostly invisible, except that the I/O is faster, and the compressed  
files take up a lot less disk space. The use of compressed netCDF has  
been fully integrated into the workflow at COLA, and has quickly  
become essential to our operations. We encourage all netCDF users to  
try it out and see for yourselves how much time and disk space this  
data format can save. The netCDF-4 support includes new commands (q  
cache, q cachesf, set cachesf, set chunksize), new options to 'set  
sdfwrite' (-nc3/-nc4, -chunk, -zip, -flt/-dbl), and a new descriptor  
file entry: CACHESIZE. Please begin by reading the User's Guide page  
entitled "Reading and Writing Compressed Data Sets" at http://iges.org/grads/gadoc/compression.html 
  . A side benefit to the netCDF-4 development was that it led to an  
improvement in the HDF5 interface, which is now significantly faster  
than in the previous release.

GrADS version 2.0.a8 also supports reading and drawing shapefiles. The  
shapefile interface is adapted from an original design by Graziano  
Giuliani. There are several new commands: 'draw shp', 'q shp', 'q  
dbf', and 'set shpopts', and a User's Guide page entitled "Drawing and  
Querying the Contents of a Shapefile" at http://iges.org/grads/gadoc/shapefiles.html 
  .

COLA's work with extremely high resolution data sets led to a bunch of  
changes to the GRIB interface. We added support for GRIB1 and GRIB2  
files that are greater than 2Gb. This is handled with a "-big" option  
to gribmap. A simple change to the user interface, but a fairly  
significant change to code "under the hood." The gribmap utility now  
also supports the "-b" option for GRIB2 data sets, a option that is  
required for the new CFS Reanalysis. Both gribmap and wgrib have been  
modified to support ECMWF grib files that have record lengths bigger  
than 8MB.

There is a new graphics output option that is useful for the  
interactive display of high-resolution data: 'set gxout imap'. This  
quickly draws shaded grid boxes just like 'gxout grfill', but the  
metafile is not updated so printim and print will not work. But it  
saves a lot of time when browsing through data and 'fishing' for  
something interesting to look at.

Two final miscellaneous items in the new release:
* Added template substitution strings %t4, %t5, %t6, %tm4, %tm5, %tm6
* New command 'q contours' returns contour colors and levels

Finally, if you have not done so already, please subscribe to the new  
forum, as the folks at CINECA will be shutting down gradsusr at list.cineca.it 
  very soon.

--Jennifer

p.s. For those of you that build GrADS from src, the configure script  
will look for $SUPPLIBS/bin/nc-config to find out if the netcdf  
library is DAP-enabled. I have also added libncurses.a to the supplibs  
collection, in an effort to make the linux builds more portable.  
Please look at http://iges.org/grads/gadoc/supplibs.html for links to  
all the latest versions of the libraries that I am using. There are  
newer versions of curl, hdf5, and netcdf, and libdap and gadap had be  
be rebuilt with the newer version of curl.

--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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