Re: regridding problem

From: David Brown <dbrown_at_nyahnyahspammersnyahnyah>
Date: Wed Feb 20 2013 - 11:20:55 MST

Sorry I had not seen Dennis' message when I wrote this. He is correct that it is an issue with the regridding as well and not strictly a plotting issue, although I think the plotting is probably also involved for the reasons stated below.
 -dave

On Feb 20, 2013, at 11:09 AM, David Brown wrote:

> I think this is strictly a plotting issue. The algorithm for the default "AreaFill" plotting does not plot the grid points directly adjacent to areas containing missing values, whereas the "RasterFill" method (in non-smoothed mode) does plot these points (cells really). With a finer resolution this is not so evident because there are more adjacent cells containing actual data.
> -dave
>
>
> On Feb 20, 2013, at 9:12 AM, cheryl Ma wrote:
>
>> Yes. It works. Thanks, Dennis.
>>
>> why it is need to set Raster mode for 2x5 data, but no need for 1x1? is there any criterion?
>>
>>
>> On Wed, Feb 20, 2013 at 10:51 AM, Dennis Shea <shea@ucar.edu> wrote:
>> When you plot this grid,
>>
>> res@cnFillMode = "RasterFill" ; Raster Mode
>>
>> This may help
>>
>>
>> On 2/20/13 8:44 AM, cheryl Ma wrote:
>> Hi all,
>>
>> I am regridding a nc file data (data.nc) in 1x1 to a new data nc file (
>> regrid_data.nc) in 2x5. It seems the ncl script I used below works fine (no
>> error information etc.). But plots (attached) created by using these two
>> files look different. Could anyone tell me what is wrong?
>>
>> I have uploaded the files data.nc and regrid_data.nc to the ftp site under
>> incoming.
>> Thanks,
>> Xiaoyan
>>
>> ==========================================
>> begin
>> f = addfile ("data.nc", "r")
>> var0=f->Deep_Blue_Aerosol_Optical_Depth_550_Land_QA_Mean
>> printVarSummary(var0)
>> printVarSummary(var0)
>> ;create a sequence for the new values of lat
>> newlat=fspan(-85.0,85.0,85)
>> ;create a sequence for the new values of lon
>> newlon=fspan(-180.0,180.0,72)
>> newlat@units = "degrees_north"
>> newlon@units = "degrees_east"
>> var=linint2(var0&lon,var0&lat,var0,True,newlon,newlat,0)
>> var!0 = "LAT"
>> var!1 = "LON"
>> var&LAT = newlat
>> var&LON = newlon
>> printVarSummary(var)
>> fout=addfile("regrid_data.nc","c")
>> fout@title="Regrid_85*72"
>> fout->var=var
>> end
>>
>>
>>
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Received on Wed Feb 20 11:21:15 2013

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