[ncl-talk] Significance plot in overlay not showing up

Hoffman Cheung hoffmancheung at gmail.com
Wed Nov 23 03:43:33 MST 2016


Hi Ipshita,

I think the sample size of your data for doing the significant test is
small (sX = 7 and sY = 4).
If you set the minimum contour intervals for showing the significant test
to be 95, probably none of the data pass this confidence level.

 res1 at cnLevelSelectionMode = "ManualLevels"   ; manually specify contour
levels
 res1 at cnMinLevelValF       = 95             ; min level
 res1 at cnMaxLevelValF       = 100             ; max level
 res1 at cnLevelSpacingF      =  1              ; contour interval

You may use printMinMax(alpha,True) to see the maximum value of alpha.

Cheers,
Hoffman




2016-11-23 2:38 GMT+01:00 Ipshita Majhi <ipmajhi at alaska.edu>:

> Dear NCl,
>
> I am trying to overlay two plots. But the significance plot does not show
> up, and there are no errors as such. I would be grateful if you could guide
> me on this.
>
>
>
> ;*******************************************
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> ;*******************************************
>
> ;*************************************************
> ;Reading in Storm track data by Peter Beinek 2016
> ;*************************************************
>  a=addfile("~/Documents/NCL_files/Storm_tracks/cyclcnt_monthly_80-14.nc
> ","r")
>
>  vNames = getfilevarnames(a) ; get variable names of all groups on file
>
>  ;print (vNames)               ; print all variable names on file
>
>  dens=a->dens
>  time=a->time
>  lat=a->lat
>  lon=a->lon
> ;**************************************************
> ;Doing composite analysis for the years
> ;with high and low monsoon
> ;High rainfall years: 1990,1994,1999,2000,2001,2008,2013
> ;Low rainfall years: 1987,1991,2009,2012
> ;***************************************************
>
> ;***************************************************
> ;Now extracting the years with high rainfall
> ;***************************************************
>
> ;********************
> ;Extracting for 1990
> ;********************
> st1990=dens({119:130},:,:)
>
> ;*******************
> ;Extracting for 1994
> ;*******************
> st1994=dens({167:178},:,:)
> ;********************
> ;1999
> ;*******************
> st1999=dens({227:238},:,:)
> ;********************
> ;2000
> ;*********************
> st2000=dens({239:250},:,:)
> ;*********************
> ;2001
> ;********************
> st2001=dens({251:262},:,:)
> ;********************
> ;2008
> ;********************
> st2008=dens({335:346},:,:)
> ;********************
> ;2013
> ;*********************
> st2013=dens({395:406},:,:)
> ;*********************
>
> ;*****************************************
> ;This averaging all the high years
> ;*****************************************
>
> st_highyrs= [/st1990,st1994,st1999,st2000,st2001,st2008,st2013/]
>
>  ListSetType(st_highyrs, "join")
>  jab = st_highyrs[:]
> ; print(dimsizes(jab))
>  zAvg = dim_avg_n_Wrap(jab,0)  ; ==> zAvg(12,nlat,nlon)
> ; print(dimsizes(zAvg))
>
> zAvg!1="lat" ; name dimensions
> zAvg!2="lon"
> zAvg&lat = dens&lat ; assign coordinate values and
> zAvg&lon =dens&lon ; units attributes
>  copy_VarAtts(dens,zAvg)
>  copy_VarCoords_1(dens,zAvg)
>  zAvg&lat at units = "degrees_north"
>  zAvg&lon at units = "degrees_east"
>
> ;*********************************************
> ;Now reading in the years with low rainfall data
> ;For storm track 1987,1991,2009,2012
> ;**********************************************
>
> ;********************
> ;1987
> ;*********************
> st1987=dens({83:94},:,:)
> ;*********************
> ;********************
> ;1991
> ;*********************
> st1991=dens({131:142},:,:)
> ;*********************
> ;********************
> ;2009
> ;*********************
> st2009=dens({335:346},:,:)
> ;*********************
> ;*********************
> ;2012
> ;*********************
> st2012=dens({383:394},:,:)
> ;*********************
> ;*****************************************
> ;This averaging all the low years
> ;*****************************************
>
> st_lowyrs= [/st1987,st1991,st2009,st2012/]
>
> ListSetType(st_lowyrs, "join")
> jab1 = st_lowyrs[:]
> ;print(dimsizes(jab1))
>
> ;******************************************
> ;This is to calculate the std
> ;******************************************
>  zStd1=dim_stddev_n_Wrap( jab1, 0 )
>
> zAvg1 = dim_avg_n(jab1,0)  ; ==> zAvg(12,nlat,nlon)
>
> zAvg1!1="lat" ; name dimensions
> zAvg1!2="lon"
> zAvg1&lat = dens&lat ; assign coordinate values and
> zAvg1&lon =dens&lon ; units attributes
>  copy_VarAtts(dens,zAvg1)
>  copy_VarCoords_1(dens,zAvg1)
>  zAvg1&lat at units = "degrees_north"
>  zAvg1&lon at units = "degrees_east"
>
>
> ;******************************************
> ;Difference between high and low years
> ;******************************************
>
> zDiff=zAvg-zAvg1
>
> zDiff!1="lat" ; name dimensions
> zDiff!2="lon"
> zDiff&lat = dens&lat ; assign coordinate values and
> zDiff&lon =dens&lon ; units attributes
>  copy_VarAtts(dens,zDiff)
>  copy_VarCoords_1(dens,zDiff)
>  zDiff&lat at units = "degrees_north"
>  zDiff&lon at units = "degrees_east"
>  zDiff= smth9(zDiff, 0.5, 0.25, True)
>
>
>  ;*****************************************
>  ;Calculating significance test
>   siglvl  = 0.05
>   aveX    =dim_avg_n_Wrap(jab,0)
>   aveY    = dim_avg_n_Wrap(jab1,0)
>   varX    = dim_variance_n_Wrap( jab, 0 )
>   varY    = dim_variance_n_Wrap( jab1, 0 )
>   sX      = 7
>   sY      = 4
>
>    alpha = 100.*(1. - ttest(aveX,varX,sX, aveY,varY,sY, True, False))
>    printMinMax(alpha,False)
>
> ; sig_ alpha = mask( alpha,  alpha.eq.100,False)
> ;sig_ alpha = mask( alpha,  alpha.le.90,False)
>
>
> alpha!0="lat" ; name dimensions
> alpha!1="lon"
> alpha&lat = dens&lat ; assign coordinate values and
> alpha&lon =dens&lon ; units attributes
>  copy_VarAtts(dens,alpha)
>  copy_VarCoords_1(dens,alpha)
> alpha&lat at units = "degrees_north"
>  alpha&lon at units = "degrees_east"
>
> ;**************************************************
> ; Now plotting the storm track
> ;**************************************************
> ;*************************************************
>   plot = new(2,graphic)
>
>   ;************************************************
> ; create plot
> ;************************************************
>  wks = gsn_open_wks("X11","Composite_high_low_storm_tracks_sig_dec_april")
>               ;
>
>  gsn_define_colormap(wks, "BlueWhiteOrangeRed")
>
> ;************************************************
> ;Composite
> ;************************************************
>    res                     = True
>   res at gsnDraw             = False            ; don't draw
>   res at gsnFrame            = False            ; don't advance frame
>   res at cnFillOn             = True                ; turn on color
>   res at cnLinesOn            = False               ; turn off contour lines
>   res at cnLevelSpacingF      = 0.1                   ; contour interval
>   res at cnLevelSelectionMode = "ManualLevels";
>   res at cnMinLevelValF       = -0.5             ; min level
>   res at cnMaxLevelValF       =0.5
>   res at mpMinLatF          = 30          ; choose a subregion
>   res at mpMaxLatF          = 90.
>   res at mpMinLonF          = 0         ; choose a subregion
>   res at mpMaxLonF          = 180.
>   res at lbLabelBarOn        = False           ; turn off individual cb's
>
> ;*****************************************************
> ;Significance
> ;*****************************************************
>   res1                     = True
>  res1 at gsnDraw              = False           ; Do not draw plot
>  res1 at gsnFrame             = False           ; Do not advance frome
>  res1 at cnFillOn             = True
>  res1 at cnMonoFillColor      = True
>  res1 at cnMonoFillPattern    = False
>  res1 at lbLabelBarOn        = False                            ; turn off
> label bar
>  res1 at cnLevelSelectionMode = "ManualLevels"   ; manually specify contour
> levels
>  res1 at cnMinLevelValF       = 95             ; min level
>  res1 at cnMaxLevelValF       = 100             ; max level
>  res1 at cnLevelSpacingF      =  1              ; contour interval
>  res1 at gsnSpreadColors      = False
>  res1 at cnInfoLabelOn       = False       ; turn off info label
>  res at cnLineLabelsOn = False
>  res1 at cnFillPatterns       =  (/17,17,17,17,17,17,17,17,17,17/)
>
>
>   scale   = 1.0
>   dotsize = 0.003
>   res1 at cnFillScaleF   = scale
>   res1 at cnFillDotSizeF = dotsize
>   ;****************************************************
>
>
>
>   plotA= gsn_csm_contour_map(wks,zDiff(3,:,:), res)  ;
>   plotB =  gsn_csm_contour(wks,alpha(3,:,:),res1)  ; create plot
>    overlay(plotA,plotB)                      ; result will be plotA
>   plot(0) = plotA
>
>   plotC = gsn_csm_contour_map(wks,zDiff(11,:,:), res)  ;
>   plotD =  gsn_csm_contour(wks,alpha(11,:,:),res1)  ; create plot
>
>   overlay (plotC, plotD)
>   plot(1) = plotC
>
>
>
>
>   resP                    = True                 ; modify the panel plot
>  resP at gsnFrame           = False                ; don't advance panel plot
>
>
> resP at gsnPanelFigureStrings= (/ "April" ,"December"/) ;
> resP at gsnPanelFigureStringsFontHeightF=0.01
> resP at amJust   = "TopLeft"
> resP at gsnPanelFigureStringsBackgroundFillColor = (/-1/)
> resP at txString           = "Storm tracks difference between high and low
> MJ years"
> resP at gsnPanelLabelBar    = True                ; add common colorbar
> resP at lbLabelFontHeightF  = 0.01               ; make labels smaller
> resP at lbOrientation       = "vertical" ; vertical label bar
>  ;
>   gsn_panel(wks,plot,(/2,1/),resP)
>
>
>  frame(wks)
> ;===========================================
>
> --
> Ipshita Majhi
> PhD Candidate
> University of Alaska , Fairbanks
> Atmospheric Science Department
> (907)978-4220 ipmajhi at alaska.edu
>
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