title: Opening multiple file in GrADS
body: <p>Hopefully this question is simple and easy enough to be solved.</p>
  
  <p>I am having a trouble in opening the second file in GrADS. Suppose I have two files. The first is "sst06.ctl" and the second is "sst07.ctl", and within each files, there is only one variable named "sst"</p>
  
  <p>Below are what happened when I tried opening both of them together:</p>
  
  <pre><code>ga-&gt; open sst06.ctl
  Scanning description file:  sst06.ctl
  Data file rcp4.5/y2006/sst is open as file 1
  LON set to 0 360 
  LAT set to -89.5 89.5 
  LEV set to 1000 1000 
  Time values set: 2006:1:1:0 2006:1:1:0 
  E set to 1 1 
  ga-&gt; q file
  File 1 : 
    Descriptor: sst06.ctl
    Binary: rcp4.5/y2006/sst
    Type = Gridded
    Xsize = 360  Ysize = 180  Zsize = 37  Tsize = 365  Esize = 1
    Number of Variables = 1
       sst  0  99  sea surface temperature [K]
  ga-&gt; d sst
  Contouring: -0 to 30 interval 3 
  ga-&gt; c
  ga-&gt; open sst07.ctl 
  Scanning description file:  sst07.ctl
  Data file rcp4.5/y2007/sst is open as file 2
  ga-&gt; d sst.2
  Data Request Warning:  Request is completely outside file limits
    Entire grid contents are set to missing data 
    Grid limits of file:     X = 1 360  Y = 1 180  Z = 1 37  T = 1 365  E = 1 1 
    Grid limits of request:  X = 0 361  Y = 1 180  Z = 1 1  T = -364 -364  E = 1 1 
    Warning issued for variable = sst.2
  Cannot contour grid - all undefined values
  </code></pre>
  
  <p>Basically, I cannot plot the second file (sst07.ctl) and it produced "entire grid undefined" plot. Of course one might suspect that there is something wrong with the file "sst07.ctl". However if I only open "sst07.ctl" file alone, there is no problem as it can be successfullty contoured as it was with the "sst06.ctl" file previously. Below is the message:</p>
  
  <pre><code>ga-&gt; reinit
  No hardcopy metafile open
  All files closed; all defined objects released;
  All GrADS attributes have been reinitialized
  ga-&gt; open sst07.ctl 
  Scanning description file:  sst07.ctl
  Data file rcp4.5/y2007/sst is open as file 1
  LON set to 0 360 
  LAT set to -89.5 89.5 
  LEV set to 1000 1000 
  Time values set: 2007:1:1:0 2007:1:1:0 
  E set to 1 1 
  ga-&gt; q file
  File 1 : 
    Descriptor: sst07.ctl
    Binary: rcp4.5/y2007/sst
    Type = Gridded
    Xsize = 360  Ysize = 180  Zsize = 37  Tsize = 365  Esize = 1
    Number of Variables = 1
       sst  0  99  sea surface temperature [K]
  ga-&gt; d sst
  Contouring: -0 to 30 interval 3 
  </code></pre>
  
  <p>The same error happened if I change the order of file opening (sst07.ctl first). The "sst06.ctl" file that is opened as the second file would result in an entire grid undefined message for the latter opened file. Below is the message:</p>
  
  <pre><code>ga-&gt; reinit
  ga-&gt; open sst07.ctl 
  Scanning description file:  sst07.ctl
  Data file rcp4.5/y2007/sst is open as file 1
  LON set to 0 360 
  LAT set to -89.5 89.5 
  LEV set to 1000 1000 
  Time values set: 2007:1:1:0 2007:1:1:0 
  E set to 1 1 
  ga-&gt; q file
  File 1 : 
    Descriptor: sst07.ctl
    Binary: rcp4.5/y2007/sst
    Type = Gridded
    Xsize = 360  Ysize = 180  Zsize = 37  Tsize = 365  Esize = 1
    Number of Variables = 1
       sst  0  99  sea surface temperature [K]
  ga-&gt; d sst
  Contouring: -0 to 30 interval 3 
  ga-&gt; c
  ga-&gt; open sst06.ctl 
  Scanning description file:  sst06.ctl
  Data file rcp4.5/y2006/sst is open as file 2
  ga-&gt; q file
  File 1 : 
    Descriptor: sst07.ctl
    Binary: rcp4.5/y2007/sst
    Type = Gridded
    Xsize = 360  Ysize = 180  Zsize = 37  Tsize = 365  Esize = 1
    Number of Variables = 1
       sst  0  99  sea surface temperature [K]
  ga-&gt; d sst.2
  Data Request Warning:  Request is completely outside file limits
    Entire grid contents are set to missing data 
    Grid limits of file:     X = 1 360  Y = 1 180  Z = 1 37  T = 1 365  E = 1 1 
    Grid limits of request:  X = 0 361  Y = 1 180  Z = 1 1  T = 366 366  E = 1 1 
    Warning issued for variable = sst.2
  Cannot contour grid - all undefined values 
  </code></pre>
  
  <p>Anybody willing to help me with this? Thanks before!</p>
  
  <h2>EDIT1: Response to Ngoan Tran's post</h2>
  
  <p>This is the result of your suggestion.</p>
  
  <pre><code>ga-&gt; reinit
  No hardcopy metafile open
  All files closed; all defined objects released;
  All GrADS attributes have been reinitialized
  ga-&gt; open sst07.ctl 
  Scanning description file:  sst07.ctl
  Data file rcp4.5/y2007/sst is open as file 1
  LON set to 0 360 
  LAT set to -89.5 89.5 
  LEV set to 1000 1000 
  Time values set: 2007:1:1:0 2007:1:1:0 
  E set to 1 1 
  ga-&gt; d sst
  Contouring: -0 to 30 interval 3 
  ga-&gt; open sst06.ctl
  Scanning description file:  sst06.ctl
  Data file rcp4.5/y2006/sst is open as file 2
  ga-&gt; set dfile 2
  Default file set to: rcp4.5/y2006/sst 
  ga-&gt; d sst
  Data Request Warning:  Request is completely outside file limits
    Entire grid contents are set to missing data 
    Grid limits of file:     X = 1 360  Y = 1 180  Z = 1 37  T = 1 365  E = 1 1 
    Grid limits of request:  X = 0 361  Y = 1 180  Z = 1 1  T = 366 366  E = 1 1 
    Warning issued for variable = sst
  Cannot contour grid - all undefined values 
  ga-&gt; 
  </code></pre>
  
  <p>Any ideas?</p>