<div dir="ltr"><div><div><div>Hi Giorgia,<br></div>I think you need to change stres@cnLevelSelectionMode = "ManualLevels". If you leave that set to "ExplicitLevels" then you would need to set your contour levels via stres@cnLevels.<br><br></div>As far as noise goes, NCL does not apply any kind of smoothing to your data. You can turn smoothing on by setting stres@cnSmoothingOn = True.<br><br><a href="http://www.ncl.ucar.edu/Document/Graphics/Resources/cn.shtml#cnSmoothingOn">http://www.ncl.ucar.edu/Document/Graphics/Resources/cn.shtml#cnSmoothingOn</a><br></div>(Note that there are other resources cited that control the degree of smoothing.)<br><div><br></div><div>Alternatively, you can smooth the data yourself using, for example, smth9_Wrap:<br><a href="https://www.ncl.ucar.edu/Document/Functions/Contributed/smth9_Wrap.shtml">https://www.ncl.ucar.edu/Document/Functions/Contributed/smth9_Wrap.shtml</a><br></div><div>(I use smth9_Wrap so that I know exactly how the data is being smoothed.)<br></div><div><br></div><div>Hope that all helps. If you have any further questions please respond to the ncl-talk email list.<br>Adam<br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Sep 8, 2014 at 12:08 PM, <span dir="ltr"><<a href="mailto:giorgia.verri@cmcc.it" target="_blank">giorgia.verri@cmcc.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear ncl,<br>
find enclosed a latlo nmap of 500hPa geopotential height and isolines of<br>
mean sea level pressure. I used "gsn_csm_contour" to plot isobars but I<br>
have 2 problems:<br>
1) isolines show noise<br>
2) I selected minlevel, maxlevel and levelspacing in the ncl script but<br>
those in the picture are different.<br>
I also attached the ncl script I wrote for plotting<br>
Thanks<br>
Cheers<br>
Giorgia<br>
<br>
<br>
<br>
<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br><div dir="ltr"><div><div><div><span><font color="#888888">Adam Phillips <br></font></span></div><span><font color="#888888">Associate Scientist, </font></span><span><font color="#888888">Climate and Global Dynamics Division, NCAR<br></font></span></div></div><div><span><font color="#888888"><a href="http://www.cgd.ucar.edu/staff/asphilli/" target="_blank">www.cgd.ucar.edu/staff/asphilli/</a> </font></span><span><font color="#888888">303-497-1726 </font></span></div><span><font color="#888888"></font></span><div><div><span><font color="#888888"><br></font></span><div><span><font color="#888888"><a href="http://www.cgd.ucar.edu/staff/asphilli" target="_blank"></a></font></span></div></div></div></div>
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