[ncl-talk] Fwd: Query

Thu Aug 28 13:24:32 MDT 2014

Hi Kunal,

I think what you want is the land-sea mask that is distributed with NCL.
Look at example 5 on the page http://ncl.ucar.edu/Applications/mask.shtml .
The first example, which you were trying to use it seems, expects the file
you load to have a variable orography associated with it. This is not the
default behavior for netcdf files! Example 5 on the other hand uses the
land-sea mask that comes with NCL and you can use that to mask values over
the ocean or over land without having to specify your own orography data.

Maria

On Thu, Aug 28, 2014 at 8:59 AM, Mary Haley <haley at ucar.edu> wrote:

> Kunal,
>
> You need to look at your code more carefully before you send it to ncl
> talk.
>
> You are reading the same variable twice:
>
> ncl 7> ts = in->TotCH4_A(:,:)
> ncl 8> oro = in->TotCH4_A(:,:)
>
> You need to look at your file and determine what the correct name of the
> "oro" variable is, and use this and not "TotCH4".
>
> You can see a list of all variable names on the file by typing:
>
> print(getfilevarnames(in))
>
> If it's still not clear which variable to use, then typing:
>
> print(in)
>
> will give you more idea about the contents of the file.
>
> You can also use "ncl_filedump", but you need to run this from the UNIX
> command line, and not from the "ncl" interactive prompt:
>
>
> ncl_filedump /home/kunal/14-01.nc
>
> --Mary
>
>
>
> On Thu, Aug 28, 2014 at 6:38 AM, Kunal Bali <kunal.bali9 at gmail.com> wrote:
>
>> How to add the valid values in scalar field. I have attached screen-shot
>> of running ncl. please look at that.
>>
>> ncl 3> load "/usr/local/lib/ncl/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>> ncl 4> load "/usr/local/lib/ncl/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>> ncl 5> begin
>> ncl 6> in = addfile("/home/kunal/14-01.nc","r")
>> ncl 7> ts = in->TotCH4_A(:,:)
>> ncl 8> oro = in->TotCH4_A(:,:)
>> ncl 9> land_only = ts
>> ncl 10> land_only = mask(ts,oro,1)
>> ncl 11> wks = gsn_open_wks("x11","mask")
>> ncl 12> gsn_define_colormap(wks,"BlAqGrYeOrRe")
>> ncl 13> res = True
>> ncl 14> res at cnFillOn = True
>> ncl 15> res at cnLinesOn = False
>> ncl 16> res at tiMainString = "Land Only"
>> ncl 17> plot = gsn_csm_contour_map_ce(wks,land_only,res)
>> ncl 18> end
>> warning:ContourPlotInitialize: no valid values in scalar field;
>> ContourPlot not possible:[errno=1101]
>>
>>
>> Kunal Bali
>> Research Scholar
>> Radio & Atmospheric Science Division
>> CSIR - National Physical Laboratory
>> New Delhi - 110012
>>
>>
>>
>>
>>
>>
>>
>> On Thu, Aug 28, 2014 at 5:27 PM, Alan Brammer <abrammer at albany.edu>
>> wrote:
>>
>>> Dear Kunali,
>>>    The error tells you exactly what is wrong.
>>>
>>> ncl 5> oro = in->ORO(:,:)
>>> fatal:["Execute.c":6321]:variable (ORO) is not in file (in)
>>> fatal:["Execute.c":8565]:Execute: Error occurred at or near line 5
>>>
>>> You're trying to load a variable ORO from the file, but a variable by
>>> that name does not exist in the file.  I'd recommend running  ncl_filedump
>>> /home/kunal/14-01.nc   and check the variables in the file.
>>> Or add print(getfilevarnames(in)) to the script after you load the file.
>>>
>>>
>>> Once past that error, as long as oro is equal to 1 over the ocean then
>>> you're good. Otherwise you may want an adjustment on this example from the
>>> ncl webpage for  (oro.le.0)
>>>  ; More advanced case mask a at locations where ma0 is not-equal-to 2
>>>
>>>
>>>
>>> ;
>>>     out1 = *mask*( a, (ma0.ne.2), True)
>>>
>>> ncl 6> land_only = ts
>>> ncl 7> land_only = mask(ts,oro,1)
>>>
>>>
>>>
>>> Good Luck,
>>>
>>> Alan Brammer
>>>
>>>
>>> On Thu, Aug 28, 2014 at 7:41 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>> wrote:
>>>
>>>> Hello
>>>> I am trying to use the masking scripts for generating data only on
>>>> land. but i am getting error. My scripts is given below.
>>>>
>>>> In this i am not getting the means of oro (line -5).
>>>> Could any one suggest me to how to correct this scripts or how to
>>>> visualize the data on land only.
>>>>
>>>> ncl 0> load "/usr/local/lib/ncl/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>>> ncl 1> load "/usr/local/lib/ncl/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>>>> ncl 2> begin
>>>> ncl 3> in = addfile("/home/kunal/14-01.nc","r")
>>>> ncl 4> ts = in->TotCH4_A(:,:)
>>>> ncl 5> oro = in->ORO(:,:)
>>>> ncl 6> land_only = ts
>>>> ncl 7> land_only = mask(ts,oro,1)
>>>> ncl 8> wks = gsn_open_wks("x11","mask")
>>>> ncl 9> gsn_define_colormap(wks,"BlAqGrYeOrRe")
>>>> ncl 10> res = True
>>>> ncl 11> res at cnFillOn = True
>>>> ncl 12> res at cnLinesOn = False
>>>> ncl 13> res at gsnSpreadColors = True
>>>> ncl 14> res at gsnSpreadColorStart = 10
>>>> ncl 15> res at gsnSpreadColorEnd = 96
>>>> ncl 16> res at cnLevelSpacingF = 3
>>>> ncl 17> res at lbLabelString = 4
>>>> ncl 18> res at tiMainString = "Land Only"
>>>> ncl 19> plot = gsn_csm_contour_map_ce(wks,land_onl,res)
>>>> ncl 20> end
>>>> fatal:["Execute.c":6321]:variable (ORO) is not in file (in)
>>>> fatal:["Execute.c":8565]:Execute: Error occurred at or near line 5
>>>>
>>>>
>>>> Thank You
>>>> Kunal Bali
>>>> Research Scholar
>>>> Radio & Atmospheric Science Division
>>>> CSIR - National Physical Laboratory
>>>> New Delhi - 110012
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>>>>
>>>
>>
>>
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