NOAA / NWS's Meteorological Development Laboratory
Degrib (NDFD GRIB2 Decoder)
Subject: Degrib version 1.12
Date: Mon, 12 May 2003 20:57:16 -0400
Organization: DOC/NOAA/NWS - National Weather Service
To: Arthur Taylor
You all have the unique distinction of being registered on my degrib
(aka NDFD_GRIB2Decoder) mailing list (all 53 of us) (I'd like to
welcome: crm, Michael Dutter, arnold and jj31571) (for those of you
keeping track, I know last time I said there were 52 of us, but 3 of the
emails bounced). I'd also like to send Mike Dutter a special Hello (as
he used to work with me here at MDL).
Please let me know (email me) if you want to unregister.
I just wanted to let you all know that I have just finished putting
together version "1.12" (last one that I announced was "1.1" on
The newest version of the program is on:
New to release 1.12:
1) Fixed the poly .shp option a little. Not sure, but I think I was
indexing the .shp files incorrectly in version 1.1. Much more confident
with the current version.
2) .dbf file can now handle the default missing value from GRIB1.
Originally the .dbf file held the data in a 10.3 ascii field (that is 10
digits with 3 decimals). The default GRIB1 missing value is 9.999 * 10
^ 21, which can't fit in the 10 digit field. The .dbf file now expands
(or contracts) according to what data is being stored in it.
3) Cleaned up the .ave script (which is an ArcView Avenue script used to
get the correct map projection when working with ESRI Spatial Analyst),
so that it is more user friendly.
4) Can now handle polar stereographic, lat/lon and mercator grids,
(although I only have sample data for the polar stereographic case).
This item currently doesn't matter for NDFD as they only use Lambert
Conformal (which I already handled), but it is useful if you want to
take MDL's MOS GRIB1 files (polar stereographic) located at
(http://weather.noaa.gov/pub/SL.us008001/DF.gr1/DC.mos/) and convert
them to .shp file.
5) Created a -nMissing option, which allows one to NOT store the missing
values in the .shp files. This is EXTREMELY advantageous, because a
completely populated NDFD grid of maxt has about 373,000 missing values
(out of 739,000 points) (roughly %50.5 missing). If one does not
include the missing values, the .shp / .shx / .dbf files are 1/2 the
size, and ESRI can draw the data TWICE as fast. This does not help the
.flt option, but ESRI handles that fast enough as is.
6) Improved the GUI to have access to some of the functions that could
only be accessed from the command line before.
7) Added a -Decimal option. Originally the data was being truncated to
3 decimals (in the .dbf files)... Now the default is rounding to 3
decimals, but one can choose anywhere from 0 decimals to 17. (More
decimals than that and a double (real * 8) can't discern it). Note for
the .flt file we are using floats or (real * 4) so 7 decimals is the
8) Got it to compile on the New IBM mainframe systems. Turns out that
Tcl/Tk was compiled using 32 bits there, so even though I was instructed
to use 64 bits objects when compiling, it wouldn't link. Switching all
the code to 32 bit objects does work. I will be looking into the issues
related to compiling in a 64 bit environment later.
As always, I tested this release on my PC (win 2000), a Linux machine, a
HP-Unix machine, and an AIX-Unix (machine). Although I may have missed
something in my testing, it should at least compile, and run for some of
the test cases. For those of you with access to the NWS suitland
machine, my current version is in: /nfsuser/g06/we25at/degrib (on
snow/frost, I'm no longer using asp/bsp). For those with access to
MDL's GDP or NHDW machines, see: ~taylor/degrib/
Please let me know if you have problems.