[ncl-talk] Error with lonFlip
Adam Phillips
asphilli at ucar.edu
Fri Jun 15 10:33:19 MDT 2018
Hi Ipsita,
So you know: You do not need to lonFlip the data if you are plotting across
the original cyclic point. Thus, if your data originally runs from 0-360,
and you want to plot the region 20W:20E, there's no need to lonFlip it just
to plot it.
I wonder though if this is the problem: According to your printVarSummary
of the original data the cyclic point was already included:
Variable: rl
Type: float
Total Size: 221184000 bytes
55296000 values
Number of Dimensions: 4
Dimensions and sizes: [ncl_join | 20] x [ncl0 | 6] x [LAT | 320] x [LON
| 1440]
Coordinates:
LAT: [-40..40]
* LON: [ 0..360]*
I would try eliminating the cyclic point (@360 degrees) upon read in. Then
proceed with your script. I bet your error message is happening because you
have two longitudes at 0 when you lonFlip the array. You can see if this is
true by printing out the longitudes: print(rr&LON)
Hope that helps!
Adam
On Fri, Jun 15, 2018 at 7:59 AM Dennis Shea <shea at ucar.edu> wrote:
> I have no idea why your script is encountering is not working.
>
> *Warning:*_NhlCreateSplineCoordApprox: Attempt to create spline
> approximation for X axis failed:
>
> You have:
> *res at gsnAddCyclic = False *
> which is appropriate for the regional grid.
>
> As a wild guess, try commenting out or deleting the following line:
>
> *;; *res at mpCenterLonF = -5
>
> [SNIP]
> printVarSummary(rr) ; [ncl0 | 6] x [LAT | 42] x [LON | 122]
>
>
> * ;
> Coordinates: ; LAT:
> [-19.9373..-9.655172] ; LON:
> [-19.76373..10.25712*]
> printMinMax(rr,0)
> ;============================================================
> wks = gsn_open_wks("png","SATL") ; send graphics to PNG file
> cmap = read_colormap_file("gui_default") ; read color data
>
> res = True ; plot mods
> desired
> res at gsnMaximize = True ; Maximize plot size
> res at cnLinesOn = False ; No contour lines
> res at cnFillOn = True ; color plot desired
> res at cnFillPalette = cmap(:15,:) ; set color map
> res at cnLineLabelsOn = False
>
> *res at gsnAddCyclic = False * * ; regional data ... not global*
> res at mpMinLatF = -20 ; zoom in on map
> res at mpMaxLatF = -10
> res at mpMinLonF = -20
> res at mpMaxLonF = 10
> *;;* res at mpCenterLonF = -5
> plot = gsn_csm_contour_map(wks,rr(0,:,:),res)
> [SNIP]
>
>
>
>
> On Thu, Jun 14, 2018 at 10:02 PM, Ipsita Putatunda <
> ipsita.putatunda at gmail.com> wrote:
>
>> Hi Dennis,
>> The output of my script (attached herewith) is coming as below:
>> ***************************************
>> Variable: rl
>> Type: float
>> Total Size: 221184000 bytes
>> 55296000 values
>> Number of Dimensions: 4
>> Dimensions and sizes: [ncl_join | 20] x [ncl0 | 6] x [LAT | 320] x
>> [LON | 1440]
>> Coordinates:
>> LAT: [-40..40]
>> LON: [ 0..360]
>> Number Of Attributes: 1
>> _FillValue : 9.96921e+36
>>
>> Variable: rflip
>> Type: float
>> Total Size: 221184000 bytes
>> 55296000 values
>> Number of Dimensions: 4
>> Dimensions and sizes: [ncl_join | 20] x [ncl0 | 6] x [LAT | 320] x
>> [LON | 1440]
>> Coordinates:
>> LAT: [-40..40]
>> LON: [-179.8749..179.8749]
>> Number Of Attributes: 2
>> _FillValue : 9.96921e+36
>> lonFlip : longitude coordinate variable has been reordered via
>> lonFlip
>>
>> Variable: rh
>> Type: float
>> Total Size: 2459520 bytes
>> 614880 values
>> Number of Dimensions: 4
>> Dimensions and sizes: [ncl_join | 20] x [ncl0 | 6] x [LAT | 42] x [LON
>> | 122]
>> Coordinates:
>> LAT: [-19.9373..-9.655172]
>> LON: [-19.76373..10.25712]
>> Number Of Attributes: 2
>> lonFlip : longitude coordinate variable has been reordered via
>> lonFlip
>> _FillValue : 9.96921e+36
>>
>> Variable: rr
>> Type: float
>> Total Size: 122976 bytes
>> 30744 values
>> Number of Dimensions: 3
>> Dimensions and sizes: [ncl0 | 6] x [LAT | 42] x [LON | 122]
>> Coordinates:
>> LAT: [-19.9373..-9.655172]
>> LON: [-19.76373..10.25712]
>> Number Of Attributes: 3
>> _FillValue : 9.96921e+36
>> lonFlip : longitude coordinate variable has been reordered via
>> lonFlip
>> average_op_ncl : dim_avg_n over dimension(s): ncl_join
>> warning:_NhlCreateSplineCoordApprox: Attempt to create spline
>> approximation for X axis failed: consider adjusting trXTensionF value
>> warning:IrTransInitialize: error creating spline approximation for
>> trXCoordPoints; defaulting to linear
>> ***********************************************
>>
>> Thanks,
>> Ipsita
>>
>> On Thu, Jun 14, 2018 at 11:22 PM, Dennis Shea <shea at ucar.edu> wrote:
>>
>>> Without knowing the 'structure' of the original variable, it is hard to
>>> offer any help.
>>>
>>> As ncl-talk suggests, the user should **always include* t*he output
>>> from *printVarSummary *of the original variable.
>>>
>>> rl=f[:]->rh ; do *not* use (:,:,:,:) when
>>> importing entire variable; it is inefficient
>>> *printVarSummary(rl)*
>>> rflip=lonFlip(rl)
>>>
>>>
>>> *printVarSummary(rflip)* rh=rflip(:,:,80:121,640:761); [-20S to -10S,
>>> 20W to 10E]
>>>
>>> lat=rh&LAT
>>> lon=rh&LON
>>>
>>> rh&LAT at units = "degrees north"
>>> rh&LON at units = "degrees east"
>>> *printVarSummary(rh)*
>>> rr=dim_avg_n_Wrap(rh,0)
>>> *printVarSummary(rr)*
>>>
>>>
>>> On Thu, Jun 14, 2018 at 4:57 AM, Ipsita Putatunda <
>>> ipsita.putatunda at gmail.com> wrote:
>>>
>>>> Dear all,
>>>> I want to plot a region [10S to 20S;20W to 10E] over South Atlantic, my
>>>> script is attached herewith, which is giving warning message like below-
>>>>
>>>> *****************************************
>>>> warning:_NhlCreateSplineCoordApprox: Attempt to create spline
>>>> approximation for X axis failed: consider adjusting trXTensionF value
>>>> warning:IrTransInitialize: error creating spline approximation for
>>>> trXCoordPoints; defaulting to linear
>>>> ********************************************
>>>> Please help me in this issue. Any suggestions will be appreciated.
>>>>
>>>> Thanks in advance,
>>>> Ipsita
>>>>
>>>>
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>>>
>>
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--
Adam Phillips
Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
<http://www.cgd.ucar.edu/staff/asphilli>
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