<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi, Don -- <div>This one was tricky! Thank you for providing all the info I needed to diagnose the problem. </div><div><br></div><div>First of all, your grib files have 112 bytes of junk at the beginning of the file. One of my favorite debugging tools, the unix command 'od' gives me this: </div><div><div><br></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">> od -c -N 116 nam.t00z.awphys01.grb2.tm00</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000000 \r \n - - 4 c 7 c 8 0 6 5 3 d e 3</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000020 \r \n C o n t e n t - t y p e : </span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000040 t e x t / p l a i n ; c h a r</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000060 s e t = i s o - 8 8 5 9 - 1 \r \n</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000100 C o n t e n t - r a n g e : b</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000120 y t e s 6 6 9 5 3 5 - 1 0 4 7</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000140 9 1 0 / 2 6 7 7 4 7 2 2 \r \n \r \n</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">0000160 G R I B </span></font></div></div><div><br></div><div>In other words, your GRIB file has the following text prefixed: </div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;"><br></span></font></div><div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">--4c7c80653de3</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">Content-type: text/plain; charset=iso-8859-1</span></font></div><div><font class="Apple-style-span" face="Courier" size="3"><span class="Apple-style-span" style="font-size: 12px;">Content-range: bytes 669535-1047910/26774722</span></font></div><div><br></div></div><div>Check your nam1hr.sh script and see if you can figure out how to get rid of that. </div><div><br></div><div>Secondly, as far as GrADS is concerned, the GRIB interface changed between a7 and a8 in order to handle files > 2Gb. This meant we had to stop using a routine in the GRIB2 library (seekgb) because it does not use 8-byte integers for file position offsets. The work normally done by seekgb is coded directly in the GrADS I/O layer for version a8. Unfortunately, one thing that seekgb does that the new code in a8 does not is check for junk bytes before the 4-character string "GRIB" at the beginning of the record. I will fix this for the new release. </div><div><br></div><div>In the meanwhile, try to avoid contaminating your GRIB file with junk. And thanks for the bug report! </div><div>--Jennifer</div><div> </div><div><br></div><div><br></div><div><br><div><div>On Aug 31, 2010, at 1:04 AM, <a href="mailto:Don.VanDyke@noaa.gov">Don.VanDyke@noaa.gov</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hello,<br><br>I am noticing some strange behavior with GrADS 2.0.a8 when I try to write a netCDF file from the following grib2 files at this link. <a href="http://casil.met.fsu.edu/~dvandyke/GrADS-problem/">http://casil.met.fsu.edu/~dvandyke/GrADS-problem/</a> I created those grib2 files with the nam1hr.sh script at that link following the example shown at <a href="http://www.cpc.noaa.gov/products/wesley/fast_downloading_grib.html">http://www.cpc.noaa.gov/products/wesley/fast_downloading_grib.html</a> . Basically, they were created from standard NCEP 12 km NAM grib2 files, but they only have certain variables contained within them in order to save bandwidth. My goal is to write those variables to netCDF files, but my writenc.gs example script at <a href="http://casil.met.fsu.edu/~dvandyke/GrADS-problem/writenc.gs">http://casil.met.fsu.edu/~dvandyke/GrADS-problem/writenc.gs</a> does not work with grads2a8. It produces an error message shown at <a href="http://casil.met.fsu.edu/~dvandyke/GrADS-problem/notes.txt">http://casil.met.fsu.edu/~dvandyke/GrADS-problem/notes.txt</a> . <br><br>The interesting thing is that everything works perfectly using the previous version of GrADS (2.0.a7.1). However, I would like to use the -flt option with the sdfwrite command, and that's only available for 2.0.a8 and higher. Can anybody explain what I'm doing wrong or if this is a bug introduced with grads2a8? Thanks!<br><br>Don Van Dyke<br>NWS Tallahassee, FL <br>_______________________________________________<br>gradsusr mailing list<br><a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br>http://gradsusr.org/mailman/listinfo/gradsusr<br></div></blockquote></div><br><div apple-content-edited="true"> <div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; font-size: 12px; "><div>--</div><div>Jennifer M. Adams</div><div>IGES/COLA</div><div>4041 Powder Mill Road, Suite 302</div><div>Calverton, MD 20705</div><div><a href="mailto:jma@cola.iges.org">jma@cola.iges.org</a></div><div><br class="khtml-block-placeholder"></div><br class="Apple-interchange-newline"></div> </div><br></div></body></html>