[ncl-talk] Color filled contour disappears with contour_shade pattern

[Rick Brownrigg]

So my (very limited) understanding from the code you sent, you drew a
color-filled contour plot of the variable "rain", which was a time slice of
the variable precip from the file. Then you intended to use gsn_csm_shade
to hachure regions where rain was gt/lt .39/-.39 ?

This is speculation:

i) draw your color-filled plot as before

ii) mask out the rain variable for only the values you want:

   rain = where(rain.lt. .39 .and. rain.gt. -.39, rain at _FillValue, rain)

iii) redraw the rain variable with gsn_csm_contour_map as before, but using
cnFillPatterns instead of color

iv) overlay the two plots as in the coneff_14 example (this requires you
set res at gsnFrame = False and res at gsnDraw = False)

HTH...
Rick



On Thu, May 2, 2019 at 10:30 AM S Br <sbr.climate at gmail.com> wrote:

> Hi Rick,
> Thanks for your reply but my region of interest cover a regional lat/lon
> domain, so I can't use gsn_csm_contour(). Instead, I am using
> gsn_csm_contour_map().
> Actually, my main objective is to draw a correlation plot with contour
> filled with color and then mark pattern to the region having significant
> correlation value (see the map attached).
> For example, I have calculated the threshold value of correlation to be
> significant is 0.39. So, I want to draw patterns over the filled contour
> for the region having the correlation value below -0.39 and above 0.39.
> 'gsn_contour_shade' is working fine for this but unfortunately, I can't
> use this with gsn_csm_contour_map()
>
> Is there any otherway to achieve this?
>
> Thanks.
> SB
>
>
>
>
>
> On Thu, May 2, 2019 at 4:45 PM Rick Brownrigg <brownrig at ucar.edu> wrote:
>
>> The docs for gsn_contour_shade() state:
>>
>> You cannot mix and match color and shading with this routine. For an
>> example of drawing shaded and filled contours, see example coneff_14.ncl
>> <http://ncl.ucar.edu/Applications/coneff.shtml#ex14>.
>>
>> However, that example coneff_14 shows how to achieve the result via two
>> calls to gsn_csm_contour():
>>
>> http://ncl.ucar.edu/Applications/coneff.shtml#ex14
>>
>> Hope that helps...
>> Rick
>>
>> On Thu, May 2, 2019 at 5:39 AM S Br <sbr.climate at gmail.com> wrote:
>>
>>> Hi Users,
>>> I am trying to plot a contour map filled with color and then apply
>>> patterns to the values greater and smaller than the specified values using
>>> the function gsn_contour_shade(plot,0.5,3.0,opt)
>>>
>>> However, when I use the gsn_contour_shade and overlay, the contour
>>> filled with color disappears. I can only see the patterns without the
>>> filled contour. Please have a look at the attached image.
>>>  I am using NCL6.4.0 and my script is given below.
>>>
>>> Thank you, SB
>>>
>>> begin
>>>
>>>  in1 = addfile("precip.gpcp.mon.mean.nc","r")
>>>   rain=in1->precip(0,:,:)
>>>   printVarSummary(rain)
>>> ;************************************
>>> ;create plot
>>> ;************************************
>>>   wks = gsn_open_wks("pdf","overlay")             ; send graphics to PNG
>>> file
>>>   res                     = True
>>>   res at gsnDraw           = False         ; Don't draw plots
>>>   res at gsnFrame          = False         ; Don't advance frame
>>>   res at cnFillOn          = True          ; Turn on contour fill
>>>   res at cnLinesOn         = False         ; Turn off contour lines
>>>   res at cnFillPalette       = "MPL_YlOrRd"   ; set color map
>>>   res at tiMainString        = "Overlaying shaded contours on filled
>>> contours"
>>> ;  res at cnFillMode = "RasterFill"
>>>   res at cnLevelSelectionMode =  "ManualLevels"
>>>   res at cnMinLevelValF       = 0.0
>>>   res at cnMaxLevelValF       = 5.0
>>>   res at cnLevelSpacingF      = 0.5
>>>
>>> ;   res at gsnAddCyclic     = False
>>>    res at mpMinLatF    =   -10.0               ; only plot 30S to 30N
>>>    res at mpMaxLatF    =  54.0
>>>    res at mpMinLonF    = 30.0              ; only plot 30S to 30N
>>>    res at mpMaxLonF    = 100.0
>>>
>>>   plot = gsn_csm_contour_map(wks,rain,res)
>>>
>>>   opt = True
>>>   opt at gsnShadeFillType = "pattern"      ; pattern fill
>>>   opt at gsnShadeHigh = 2                  ; use pattern #2
>>>   opt at gsnShadeLow = 17                  ; use pattern #17
>>>   plot2 = gsn_contour_shade(plot,0.5,3.0,opt)
>>>   overlay(plot,plot2)
>>>
>>>   draw(plot)
>>>   frame(wks)
>>> end
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk at ucar.edu
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20190502/ca248c80/attachment.html>