NOAA / NWS's Meteorological Development Laboratory
Degrib (NDFD GRIB2 Decoder)
Subject: Degrib 1.84
Date: Mon, 06 Nov 2006 12:47:04 -0500
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www.weather.gov/mdl/degrib/ or www.weather.gov/mdl/NDFD_GRIB2Decoder/.
----------- General News (see:http://www.nws.noaa.gov/om/notif.htm)
On 11/1/2006, QPF became "experimental" for Hawaii (see TIN 06-66)
On 11/2/2006, there was a NDFD technical workshop in Silver Spring
Maryland whose intent was: "to provide NWS customers and partners an
opportunity to interact with NWS technical staff to discuss near term
and future requirements for enhancements to the electronic interfaces to
NDFD." The conference appears to have gone well, with various people
asking about when the next one will occur.
On 11/28/2006, the time the extra day is added to the NDFD will change
from 18Z to 22Z. (TIN 06-72)
On 12/4/2006, the XML service for the NDFD will move from experimental
status to operational status. (TIN 06-73)
----------- News about this release:
I've just finished putting together (on Friday 11/3/2006) version "1.84"
(last one that I announced was "1.83" on 9/14/2006).
This release focused primarily on some bug fixes, along with
reconfiguring to add experimental QPF in Hawaii.
1) Reconfigured code to add experimental QPF in Hawaii.
2) Albion Taylor provided a "configure / make" method of compiling
degrib as an improvement over using "make -f makefile.???" where ???
is chosen by the user to reflect which system they have. The new method
should provide support for more systems, and be more flexible in the
long run. Currently I'm supporting both the old and new methods of
compilation, but want to transition to the "configure / make" method.
3) Adjusted the hard coded values for Alaska's grid from a spacing of
5.953 km to 5.953125 km. This was because the GRIB2 files I based the
hard coded values on were erroneous. Fixing this, meant updating
/geodata/alaskatimezone.flt and /geodata/alaskadaylight.flt.
4) Fixed a bug on 64 bit compilations, by adjusting the grib2lib code to
pay attention to my 64 bit flag (rather than an environment flag).
5) Attempted to fix a sign bug when using GRIB2MISSING_s4, which was
encountered with a Japanese GRIB2 file. The file in question didn't
have a value associated with the surface. When using NCEP's GRIB2
library, signed missing 4 byte integers are returned as -1 * 231, while
unsigned missing 4 byte integers are returned as 232 -1. Previously, I
had checked all 4 byte missings by casting them to unsigned and
comparing to 232 -1. This is erroneous in the signed case, since -1 *
231 cast to a 4 byte unsigned integer becomes 231 + 1, not 232 -1.
The solution is to check signed missing 4 byte values against -1 * 231,
and unsigned missing 4 byte values against 232 -1.
6) Fixed web.tcl to use http::myAppend instead of http::append (Broke on
a version of linux), in addition fixed a minor bug when reporting the
usage of web.tcl
7) Checked in all the releases of degrib into a "subversion" repository.
Some thought is still needed as to how to post the repository. It
should provide others the ability to check out the latest "unreleased"
versions of the code, and allow them to contribute (if they so desire).
Please let me know if you have problems.