<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I updated the lterp() doc page with some more examples, including an override for the time dimension -- for when the times of the source and destination grids don't match. Below, I also cite some highly relevant information about the dimension environment and the default file from the doc page on variables:<div><br></div><div>The complete specification for a variable name is:
<ul><p><code>abbrev.file#(dimexpr,dimexpr,...)</code> where: </p>
<ul>
<code>abbrev </code>is the abbreviation for the variable as
specified in the
data descriptor file
<br>
<code>file# </code>is the file number that contains
this variable. If <code>file#</code> is absent, GrADS assumes the default file number. <br>
<code>dimexpr </code>is a dimension expression that locally
modifies the current dimension environment.
</ul>
</ul><p>
The <code>dimexpr</code> is used to override or modify the current dimension environment only for the <code>abbrev</code> variable. Only fixed dimensions can be
modified with a <code>dimexpr</code>. The <code>dimexpr</code> can be given in grid or world coordinates. <b>An important note:</b> When you specify a dimension in grid units,
GrADS always converts it to world coordinates. In general, this conversion
is done using the scaling of the <i>default file</i>. The only exception to this rule is in this case, when a
grid coordinate (x, y, z, t, or e) is supplied within a <code>dimexpr</code> as part of a variable specification. In the case of this special exception, the conversion is done using the scaling for
the file that variable is to be taken from (i.e., file number <code>file#</code>). </p><div>--Jennifer</div><div><br><div><div>On Sep 5, 2013, at 7:59 PM, Andrew Friedman wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Thanks to Jennifer and Chuck for your help.<br><br>I was able to use method 2 from Jennifer's email below.<br>The only other issue I ran into is that I needed to set the time coordinates of my coarse grid file the same as the fine grid file.<br><br>Andrew<br><br>On Sep 4, 2013, at 2:59 PM, Jennifer Adams <<a href="mailto:jma@cola.iges.org">jma@cola.iges.org</a>> wrote:<br><br><blockquote type="cite">Hi, Andrew -- <br></blockquote><blockquote type="cite">I agree that this is tricky, and I had recently updated the example in the docs to reflect the subtleties when using lterp with fwrite. I see I will have to add another example with sdfwrite -- this email has given me a good start on that ...<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Anyway, the difference between your example and mine is that in my example the default file is the destination grid and in yours the default file is the source grid. It matters what file is set to be the default file because x=1:xsize resolves to different world coordinates when you change default files. The bottom line is you want to be constraining the coordinates of the destination grid. To fix your example, you have two options: <br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">1. Switch the order of the sdfopen commands (i.e. open coarse.nc first), and then 'set x 1 number_of_points_in_coarse.nc' then change lterp command to lterp(fine.2,coarse)<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">2. Before you define the output variable, you can 'set dfile 2' and then 'set x 1 number_of_points_in_coarse.nc' and then proceed. <br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">--Jennifer<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">On Sep 4, 2013, at 4:42 PM, Andrew Friedman wrote:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><blockquote type="cite">Hi GrADS users,<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">I am using lterp to regrid a file to a coarser resolution, and saving the variable to netcdf using sdfwrite.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">My problem is that the output file has 2 additional longitudes compared to the input grid destination description file.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Similar to the example in the lterp documentation in the grads index:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">sdfopen fine.nc<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">set X 1 [number of longitude points in fine.nc]<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">sdfopen coarse.nc<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">output = lterp(fine,coarse.2,aave)<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">set sdfwrite output.nc<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">sdfwrite output<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">I've had this issue before when there is just one input file, and explicitly defining longitude with the step 'set X 1 [number of longitude points]' works to solve it. In this case however, I'm not sure how to limit the longitude dimension of the output.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Do you have ideas how I can fix this?<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Thanks,<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Andrew<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">------<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Andrew Friedman<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Graduate Student, UC Berkeley Geography<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="mailto:andfried@berkeley.edu">andfried@berkeley.edu</a><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">_______________________________________________<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">gradsusr mailing list<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="http://gradsusr.org/mailman/listinfo/gradsusr">http://gradsusr.org/mailman/listinfo/gradsusr</a><br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">--<br></blockquote><blockquote type="cite">Jennifer M. Adams<br></blockquote><blockquote type="cite">Center for Ocean-Land-Atmosphere Studies (COLA)<br></blockquote><blockquote type="cite">111 Research Hall, Mail Stop 2B3<br></blockquote><blockquote type="cite">George Mason University<br></blockquote><blockquote type="cite">4400 University Drive<br></blockquote><blockquote type="cite">Fairfax, VA 22030 <br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">gradsusr mailing list<br></blockquote><blockquote type="cite"><a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br></blockquote><blockquote type="cite"><a href="http://gradsusr.org/mailman/listinfo/gradsusr">http://gradsusr.org/mailman/listinfo/gradsusr</a><br></blockquote><br><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">
<span class="Apple-style-span" style="font-size: 12px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 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; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-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; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 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; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>--</div><div>Jennifer M. Adams<br>Center for Ocean-Land-Atmosphere Studies (COLA)<br>111 Research Hall, Mail Stop 2B3<br>George Mason University<br>4400 University Drive<br>Fairfax, VA 22030 <br><br></div><div><br class="khtml-block-placeholder"></div><br class="Apple-interchange-newline"></span></span></div></span><br class="Apple-interchange-newline">
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