<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Try getting rid of the 'scale_factor' attribute for the ndvi variable. It is set to 0, and your data are floats, so I'm not sure exactly what purpose it is serving anyway. Also, what version of GrADS are you using? <br><br><div>Jennifer<div><div><br><div><div><br><div><div>On Sep 1, 2010, at 4:36 AM, dyjbean soybean wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>hi,</div> <div> i have made a netcdf file write in fortran ,but when i open it in grads with 'sdfopen ', the following error occurs:</div> <div> </div> <div>*********************************************************************************************</div> <div> ga-> sdfopen j:/<a href="http://00apr.nc">00apr.nc</a><br>Scanning self-describing file: j:/<a href="http://00apr.nc">00apr.nc</a><br>SDF file has no discernable time coordinate.<br>SDF file j:/<a href="http://00apr.nc">00apr.nc</a> is open as file 1<br> LON set to -179.959 179.949<br>LAT set to -62.8134 89.2103<br>LEV set to 0 0<br>Time values set: 1:1:1:0 1:1:1:0<br>ga-> q file<br>File 1 : NDVI production<br> Descriptor: j:/<a href="http://ndvi2000apr.nc">ndvi2000apr.nc</a><br> Binary: j:/<a href="http://ndvi2000apr.nc">ndvi2000apr.nc</a><br> Type = Gridded<br> Xsize = 4950 Ysize = 2091 Zsize = 1 Tsize = 1<br> Number of Variables = 1<br> ndvi 0 -999 NDVI<br>ga-> d ndvi<br>SDF data variable has unsupported packed data type.<br> Data Request Error: Error for variable 'ndvi'<br> Error ocurred at column 1<br>DISPLAY error: Invalid expression<br> Expression = ndvi<br clear="all">***************************************************************************************</div> <div>based on the above problem, i made a 'ddf' file, as follows:</div> <div>++++++++++++++++++++++++++++++++++++</div> <div>dset ^<a href="http://ndvi2000apr.nc">ndvi2000apr.nc</a><br>options yrev<br>undef -9999.0<br>xdef lon 4950 linear -179.95932 0.07272727<br>ydef lat 2091 linear -62.81345 0.07272727<br>zdef lev 1 levels 1000<br>tdef time 1 linear apr2000 1mo<br> vars 1<br>ndvi=>ndvi 1 99 normalized difference vegetation index<br>endvars</div> <div>++++++++++++++++++++++++++++++++++++++++</div> <div> </div> <div>but the same error appears:</div> <div> </div> <div> ga-> xdfopen j:/ndvi2000apr.ddf<br>Scanning Descriptor File: j:/ndvi2000apr.ddf<br>SDF file j:/<a href="http://00apr.nc">00apr.nc</a> is open as file 1<br>LON set to 0 360<br>LAT set to -62.8134 89.1865<br>LEV set to 1000 1000<br> Time values set: 2000:4:1:0 2000:4:1:0<br>ga-> q file<br>File 1 : NDVI production<br> Descriptor: j:/ndvi2000apr.ddf<br> Binary: j:/<a href="http://00apr.nc">00apr.nc</a><br> Type = Gridded<br> Xsize = 4950 Ysize = 2091 Zsize = 1 Tsize = 1<br> Number of Variables = 1<br> ndvi 1 99 normalized difference vegetation index<br>ga-> d ndvi<br>SDF data variable has unsupported packed data type.<br>Data Request Error: Error for variable 'ndvi'<br> Error ocurred at column 1<br> DISPLAY error: Invalid expression<br> Expression = ndvi</div> <div>+++++++++++++++++++++++++++++++++</div> <div> </div> <div>the nc file information is below:</div> <div> filename: ndvi2000apr<br> path: <a href="http://ndvi2000apr.nc">ndvi2000apr.nc</a><br> file global attributes:<br> title : NDVI production<br> dimensions:<br> lev = 1<br> lat = 2091<br> lon = 4950<br> time = 1 // unlimited<br> variables:<br> integer lev ( lev )<br> long_name : Level<br> units : level_number</div> <div> float lat ( lat )<br> long_name : Latitude<br> units : degree_north</div> <div> float lon ( lon )<br> long_name : Longitude<br> units : degree_east</div> <div> integer time ( time )<br> long_name : TimeRecord<br> units : monthly</div> <div> float ndvi ( time, lev, lat, lon )<br> long_name : NDVI<br> units : m2m-2<br> missing_value : -9999<br> scale_factor : 0<br> _FillValue : -9999</div> <div> </div> <div>according to the abovementioned questions, any help is appreciaed, thanks</div> <div> </div> <div><br>-- <br>通讯地址：北京市朝阳区大屯路9718信箱 <br> 中国科学院遥感应用研究所<br>邮编：100101<br>电话：010-64860422<br></div> _______________________________________________<br>gradsusr mailing list<br><a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br>http://gradsusr.org/mailman/listinfo/gradsusr<br></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><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"></span></span></div></span> </div><br></div></div></div></div></div></body></html>