<div dir="ltr">There are certain variables, specifically coordinate variables, that are alluded to in the metadata when the file is read as HDF, but which are not visible as variables. To actually get the coordinate values you need to read the file as HDFEOS. The HDFEOS reader has specialized support for HDFEOS coordinates. From your print out, it appears that there are 3 different swaths in the files (in HDF terms these are represented as different groups), and 3 corresponding coordinates named 'Time'. Since I think this is an HDFEOS2 file, NCL appends the group name to variables within the group. So for example <span style="font-family:arial,sans-serif;font-size:13.63636302948px;line-height:19.0909080505371px">Time_Low_Res_Swath means the Time coordinate variable in the Low_Res_Swath group.</span><div><font face="arial, sans-serif"><span style="line-height:19.0909080505371px">The HDFEOS2 reader was written before support for groups was added to NCL, so you cannot use the group syntax. However, all the variables in the HDFEOS file should be available. Hope this helps.</span></font></div><div><font face="arial, sans-serif"><span style="line-height:19.0909080505371px"> -dave<br></span></font><div><span style="font-family:arial,sans-serif;font-size:13.63636302948px;line-height:19.0909080505371px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13.63636302948px;line-height:19.0909080505371px"><br></span></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 4, 2014 at 10:13 AM, <a href="mailto:dyjbean@gmail.com">dyjbean@gmail.com</a> <span dir="ltr"><<a href="mailto:dyjbean@gmail.com" target="_blank">dyjbean@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
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<div><span></span><br></div><div>after i have changed the suffix of <span style="background-color:transparent;font-size:10.5pt;line-height:1.5">AMSR_E_L2A_201108010017_D.hdf into </span><span style="background-color:transparent;font-size:10.5pt;line-height:1.5">AMSR_E_L2A_201108010017_D.hdf.hdfeos, there gave a </span></div><div><span style="font-size:14px;line-height:21px">another variation, the "Time" variable has new variable names: </span></div><div><span style="background-color:rgba(0,0,0,0);font-size:14px;line-height:1.5"><br></span></div><div><span style="background-color:rgba(0,0,0,0);font-size:14px;line-height:1.5">double Time_High_Res_B_Swath ( DataTrack_lo_High_Res_B_Swath )</span></div><div><span style="background-color:rgba(0,0,0,0);font-size:14px;line-height:1.5">double Time_High_Res_A_Swath ( DataTrack_lo_High_Res_A_Swath )</span></div><div><span style="background-color:rgba(0,0,0,0);font-size:14px;line-height:1.5">double Time_Low_Res_Swath ( DataTrack_lo_Low_Res_Swath )</span></div><div><br></div>
<div>above these three variables didn't appear in hdf file but in hdfeos,this is a file format change.</div><div><br></div><div><br></div><div> </div><hr style="width:210px;min-height:1px" color="#b5c4df" size="1" align="left"><span class="HOEnZb"><font color="#888888">
<div><span><div style="FONT-FAMILY:verdana;FONT-SIZE:10pt">
<div><a href="mailto:dyjbean@gmail.com" target="_blank">dyjbean@gmail.com</a></div></div></span></div>
</font></span><blockquote style="margin-top:0px;margin-bottom:0px;margin-left:0.5em"><span class=""><div> </div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm"><div style="PADDING-RIGHT:8px;PADDING-LEFT:8px;FONT-SIZE:12px;FONT-FAMILY:tahoma;COLOR:#000000;BACKGROUND:#efefef;PADDING-BOTTOM:8px;PADDING-TOP:8px"><div><b>From:</b> <a href="mailto:lijpbasin@126.com" target="_blank">李嘉鹏</a></div><div><b>Date:</b> 2014-11-04 18:32</div><div><b>To:</b> <a href="mailto:ncl-talk@ucar.edu" target="_blank">ncl-talk</a></div><div><b>Subject:</b> Re: [ncl-talk] how to read a variable in group of hdf file?</div></div></div></span><div><div class="h5"><div><div>Hi, Try `ncl_filedump AMSR_E_L2A_201108010017_D.hdf`, it might give you some hints of the corresponding variable name in NCL.</div>
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<div>On November 4, 2014 6:13:49 PM GMT+08:00, "<a href="mailto:dyjbean@gmail.com" target="_blank">dyjbean@gmail.com</a>" <<a href="mailto:dyjbean@gmail.com" target="_blank">dyjbean@gmail.com</a>> wrote:</div>
<div>>hi,</div>
<div>>i want to read a variable "Time" which is involved in group in a hdf</div>
<div>>file, a part of information of this hdf file is as follows:</div>
<div>>+++++++++++++++++++++++++++++++++++++++++++</div>
<div>>......</div>
<div>>GROUP=GeoField </div>
<div>>OBJECT=GeoField_1 </div>
<div>>GeoFieldName="Time" </div>
<div>>DataType=DFNT_FLOAT64 </div>
<div>>DimList=("DataTrack_lo") </div>
<div>>END_OBJECT=GeoField_1 </div>
<div>>OBJECT=GeoField_2 </div>
<div>>GeoFieldName="Latitude" </div>
<div>>DataType=DFNT_FLOAT32 </div>
<div>>DimList=("DataTrack_lo","DataXTrack_lo") </div>
<div>>END_OBJECT=GeoField_2 </div>
<div>>OBJECT=GeoField_3 </div>
<div>>GeoFieldName="Longitude" </div>
<div>>DataType=DFNT_FLOAT32 </div>
<div>>DimList=("DataTrack_lo","DataXTrack_lo") </div>
<div>>END_OBJECT=GeoField_3 </div>
<div>>END_GROUP=GeoField </div>
<div>>......</div>
<div>>++++++++++++++++++++++++++++++++++++++++++++++++++</div>
<div>></div>
<div>>i want to extract the "Time" in ncl, but it showed:</div>
<div>>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</div>
<div>></div>
<div>>ncl 0> ff=addfile("AMSR_E_L2A_201108010017_D.hdf","r") </div>
<div>>ncl 1> time=ff->Time </div>
<div>>fatal:["Execute.c":6321]:variable (Time) is not in file (ff) </div>
<div>>fatal:["Execute.c":8565]:Execute: Error occurred at or near line 1</div>
<div>>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</div>
<div>></div>
<div>>it seems that there doesn't exist "Time" variable in this hdf file,but</div>
<div>>it does,</div>
<div>></div>
<div>>how can i read this time info in ncl?</div>
<div>></div>
<div>></div>
<div>>thanks </div>
<div>></div>
<div>> </div>
<div>></div>
<div>></div>
<div>><a href="mailto:dyjbean@gmail.com" target="_blank">dyjbean@gmail.com</a></div>
<div>></div>
<div>></div>
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