[ncl-talk] Incorrect significance plot

[Mary Haley]

It's hard for us to look at a code with lots of calculations to try to
figure out why a plot is not correct, if we don't have access to the data.

Have you tried debugging your code, to see if any of the values you've
calculated are incorrect?

I suggest using printVarSummary and printMinMax to make sure you have the
values and metadata that you expect:

printVarSummary(corr_dec)
printMinMax(corr_dec,0)
printVarSummary(prob_dec)
printMinMax(prob_dec,0)

etcetera.

As a side, why do you have this line:

e=transpose(transpose(JJAS_1967_2012))

If you transpose an array and then transpose it again, you are going to get
the same array back.  This is an unnecessary operation.

--Mary


On Tue, Feb 2, 2016 at 11:35 AM, Ipshita Majhi <ipmajhi at alaska.edu> wrote:

> Dear NCL,
>
> I calculated correlation and am trying to plot the significance plot. The
> significance plot , is not plotting correctly, it is giving no significance
> where there is high correlation and vice versa. It will be great if you
> could point out where I am going wrong.
> Best Regards
> Ipshita
>
> ;=============================================
> ; Reading data
> ;=============================================
>
> a=addfile("~/Documents/SST/Monthly/sst.mnmean.v4.nc","r")
> JJAS
> =asciiread("~/Documents/SST/Monthly/jjas_1871_2012.txt",(/142,1/),"float")
>
> ;============================================
> ;Extracting JJAS for 1967 to 2012
> ;============================================
>
> JJAS_1967_2012=JJAS(96:141,0)
>
> e=transpose(transpose(JJAS_1967_2012))
>
> ;=============================================
> ;The dataset goes from 1854-2015
>
> sst=a->sst
>
>  copy_VarAtts(a,sst)
>  copy_VarCoords_1(a,sst)
> ;============================================
>
> ;Extracting sea surface temperature
>
> sst=a->sst
>
> ;Extracting 1967-2012 for SST
> sst_1967_2012=sst(1356:1907,:,:)
>
> copy_VarAtts(sst,sst_1967_2012)
> copy_VarCoords_1(a,sst_1967_2012)
>
> ;============================================
> ;Extracting 1871 to 2012 SST
>
> Dec_sst = new((/46,89,180/),float)
> Dec_sst at _FillValue = -9.9621e+36
>
>
> ;==========================================
> ;Extracting SST for each month
> ;========================================
>
> do nyr=0,551,12
>
> Dec_sst(nyr/12,:,:) =sst_1967_2012(nyr+11,:,:)
> end do
>
> copy_VarAtts(sst_1967_2012,Dec_sst)
> copy_VarCoords_1(sst_1967_2012,Dec_sst)
>
> ;=======================================
> ;Reordering
> ;=======================================
>
> Dec_reorder=Dec_sst(lat|:,lon|:,time|:)
>
> Dec_reorder at _FillValue = -9.9621e+36
>
> copy_VarAtts(Dec_sst,Dec_reorder)
> copy_VarCoords_1(Dec_sst,Dec_reorder)
>
> ;=====================================
>
> ;======================================
> ;Calculating Correlation
> ;======================================
>
> corr_dec=escorc(Dec_reorder,e)
> copy_VarCoords_1(Dec_reorder,corr_dec)
>
> ;===========================================
>
> ;Calculating significance
> prob_dec   = rtest(corr_dec(:,:,0),46,0)
> copy_VarCoords_1(Dec_reorder,prob_dec)
> prob_dec at _FillValue = -9.9621e+36
>
> ;==============================================
>
> ; Now plotting the Significance
>   wks  = gsn_open_wks("pdf","Significance_test")
>   gsn_define_colormap(wks,"testcmap")              ; choose colormap
>
>   res                      = True                ; make plot mods
>   res at gsnDraw = True
>   res at gsnFrame = True
>   res at cnFillOn             = True                ; turn on color
>   res at gsnSpreadColors      = True                ; use full colormap
>   res at lbLabelAutoStride    = True         ; automatic lb label stride
>
>   res at cnLinesOn            = False               ; turn off contour lines
>   res at cnLevelSelectionMode = "ManualLevels" ; manually set cnlev
>   res at cnMinLevelValF       = -1            ; min level
>   res at cnMaxLevelValF       =  1                 ; max level
>   res at cnLevelSpacingF      = 0.1                 ; contour level spacing
>
>
>
>   res at tiMainString         = "Dec SST with JJAS rainfall Regular
> 1967-2012"
>   plot= gsn_csm_contour_map_ce(wks,prob_dec,res)
>
>  ;===========================================
>
>
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