<div dir="ltr"><div><div>This question is rather unclear. The following is a &#39;shot-in-the-dark&#39;.<br></div><div>You have<br></div><div><br>        tasP = b-&gt;tas(0:364,:,:)<br>
<br>
        TIMEP = cd_calendar(tasP&amp;time,0)   ; TIMEP(ntim,6)<br>
<br>
        tasCp = tasP - 273.15  ; Convert K to C<br>
        tasCp = where(tasCp.gt.0.0, tasCp, 0.0)<br></div>        copy_VarMeta(tasP, tasCp)<br>        tasCp@units = &quot;degC&quot;<br></div>        printVarSummary(tasCp)<br><div><br><div>
        pddP  = dim_sum_n_Wrap(tasCp, 0)       ; (lat,lon)<br>
        pddP@long_name = &quot;degree days for year=&quot;+toint(TIMEP(0,0))<br>
        pddP@units = &quot;degC&quot;<br>
<br>
; Calculate ablation (PDD * 5); add meta data<br>
        Ab = pddP * 5<br></div><div>        copy_VarCoords(pddP, Ab)<br></div><div>        Ab@long_name = &quot;Ablation&quot;<br></div><div>        Ab@units           = &quot;???&quot;<br></div><div>
        printVarSummary (Ab) <br><br>;---<br>
<br><div>        Orog = c-&gt;orog(:,:)                               ; 2D (lat,lon)<br><br></div><div>        Orog_1D = ndtooned(Orog)<br></div><div>        Ab_1D     = ndtooned(Ab)<br><br></div><div>; convenience, not required, sort into ascending orography<br>
<br>     <strong>  </strong>   iorog =<strong> dim_pqsort_n</strong>(Orog_1D,1,0)<br>       x = Orog_1D(iorog)    ; clarity<br>       y = Ab_1D(iorog)<br></div><div>       print(x(0:99)+&quot;   &quot;+y(0:99))    ; print 1st 100 values<pre>
   rc = regline(x,y)<br></pre></div></div><div>or, if you have 6.2.0 <br><br></div><div>      rc =  regline_stats(x,y)  ; more information<br></div><div>      print(rc)<br></div><div><br></div><div><div><pre>    df   = rc@nptxy-2
    prob = (1 - <a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/betainc.shtml"><strong>betainc</strong></a>(df/(df+rc@tval^2), df/2.0, 0.5) )<br><br>      yReg = rc*x + rc@yintercept   ; NCL array notation 
                                    ; <em>yReg</em> is same length as <em>x</em>, <em>y</em>
    
     
      <a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/print.shtml"><strong>print</strong></a>(&quot;prob=&quot;+prob)
     
      <a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/print.shtml"><strong>print</strong></a>(x+&quot;  &quot;+yReg)</pre><a href="http://www.ncl.ucar.edu/Applications/regress.shtml">http://www.ncl.ucar.edu/Applications/regress.shtml</a>   <br>
<br></div><div><a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/regline.shtml">http://www.ncl.ucar.edu/Document/Functions/Built-in/regline.shtml</a>      <br><a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/regline_stats.shtml">http://www.ncl.ucar.edu/Document/Functions/Contributed/regline_stats.shtml</a>       <br>
<a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_pqsort_n.shtml">http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_pqsort_n.shtml</a><br></div></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Thu, Aug 7, 2014 at 12:26 PM, Lauren Jean Vargo <span dir="ltr">&lt;<a href="mailto:lvargo@unm.edu" target="_blank">lvargo@unm.edu</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello,<br>
<br>
I have a code that creates a scatter plot of 2 variables (ablation and surface altitude, both 2d arrays).<br>
<br>
Now I’m trying to 1) include a regression line on the plot, and 2) calculate the slope of that line (the regression coefficient).<br>
I’ve been trying to use regCoef since the arrays are both 2d, but the answers that are being printed are not reasonable.<br>
<br>
The files are both very large, but I can upload them if needed.<br>
<br>
I’m running ncl version 6.1.2, and the system is Darwin Kernel Version 13.3.0<br>
<br>
Here is the script:<br>
<br>
load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl&quot;<br>
load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl&quot;<br>
load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl&quot;<br>
load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl&quot;<br>
<br>
begin<br>
<br>
; Read in temperature data &amp; calculate PDD sum<br>
        b = addfile(&quot;tas_day_CCSM4_piControl_r2i1p1_09530101-09871231.nc&quot;,&quot;r&quot;)<br>
        tasP = b-&gt;tas(0:364,:,:)<br>
<br>
        TIMEP = cd_calendar(tasP&amp;time,0)   ; TIMEP(ntim,6)<br>
<br>
        tasCp = tasP - 273.15  ; Convert K to C<br>
        tasCp = where(tasCp.gt.0.0, tasCp, 0.0)<br>
        pddP  = dim_sum_n_Wrap(tasCp, 0)       ; (lat,lon)<br>
        pddP@long_name = &quot;degree days for year=&quot;+toint(TIMEP(0,0))<br>
        pddP@units = &quot;degC&quot;<br>
<br>
; Calculate ablation (PDD * 5)<br>
        Ab = pddP * 5<br>
        printVarSummary (Ab)<br>
<br>
; Read in topographic data<br>
        c = addfile(&quot;orog_fx_CCSM4_lgm_r0i0p0.nc&quot;,&quot;r&quot;)<br>
        Orog = c-&gt;orog(:,:)<br>
<br>
; Calculate regression line<br>
        rc    = regCoef (Orog,Ab)<br>
        print (rc)<br>
<br>
<br>
; Plot<br>
        res                                   = True                     ; plot mods desired<br>
        res@gsnMaximize           = True                    ; maximize plot in frame<br>
        res@xyMarkLineMode     = &quot;Markers&quot;           ; choose which have markers<br>
        res@xyMarker                  = 1                        ; choose type of marker<br>
        res@xyMarkerSizeF         = 0.005                 ; Marker size (default 0.01)<br>
<br>
        res@tiMainString        = &quot;Ablation Gradient&quot;  ; title<br>
<br>
  wks = gsn_open_wks(&quot;x11&quot;,&quot;CCSM_Ablation_gradient&quot;)<br>
  plot = gsn_csm_xy(wks,Orog(:,:),Ab(:,:),res)<br>
<br>
<br>
end<br>
<br>
Any help would be great!<br>
Thank you,<br>
<br>
Lauren Vargo<br>
<br>
<br>
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</blockquote></div><br></div>