<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>I can't allow misinformation to go out to the list uncorrected: <font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;"><b>GrADS can read any HDF file containing gridded fields. </b></span></font></div><div>This particular HDF file contains swath data. It's gridded -- there are 406 cells in the along-swath direction, and 270 cells in the across-swath direction. GrADS will read this data, but only onto an abstract x,y grid. The lat/lon values of each grid point are read in as data variables. A full 'dtype hdfsds' descriptor file would include the following lines: </div><div><br></div><div><div>x<font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">def 270 linear 1 1</span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">ydef 406 linear 1 1</span></font></div><div>tdef 1 linear ...</div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">...</span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">vars 4</span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Latitude=>scanlat 0 y,x </span></font><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Geodetic Latitude </span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Longitude=>scanlon 0 y,x </span></font><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Geodetic Longitude </span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Scan_Start_Time=>scantime 0 y,x </span></font><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">International Atomic Time at Start of Scan replicated across the Swath </span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Surface_Temperature=>tsfc 0 y,x </span></font><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">Surface_Temperature </span></font></div><div><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">endvars</span></font></div><div><br></div><div>You can add more variables, including some that have a Z axis, depending on what you'd like to look at in the file. The rest of the required descriptor file entries are discussed in the documentation page <a href="http://iges.org/grads/gadoc/SDFdescriptorfile.html">http://iges.org/grads/gadoc/SDFdescriptorfile.html</a></div><div><br></div><div>--Jennifer</div><div><br></div></div><div><br></div><div>On Oct 19, 2009, at 10:49 AM, Yan Libin wrote:</div><div><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="margin-top: 10px; margin-right: 10px; margin-bottom: 10px; margin-left: 10px; font-family: verdana; font-size: 10pt; "><div><font color="#000080" size="2" face="Verdana">a ctl is not enough</font></div></div></span></blockquote></div><br><div><div>On Oct 19, 2009, at 10:49 AM, Jayakrishnan PR wrote:</div><blockquote type="cite">... we cannot open them through grads by writing a ctl file. <br></blockquote><br></div><div><br></div><div><div>On Oct 19, 2009, at 10:26 AM, Hao He wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hi,<br> I want to read MODIS HDF file by GrADS. Unfortunately both sdfopen and<br>xdfopen do not work for me, so I need to write a complete .ctl file. But</div></blockquote></div><div><blockquote type="cite"><div>I am confused after reading the MODIS data set<br>(<a href="http://modis-atmos.gsfc.nasa.gov/MOD07_L2/format.html">http://modis-atmos.gsfc.nasa.gov/MOD07_L2/format.html</a>)</div></blockquote></div><div><blockquote type="cite"><div>I am wondering if anyone has experience on it.<br>Thanks a lot!<br><br>Hao</div></blockquote></div></body></html>