[ncl-talk] Mottled output from gsn_csm_contour_map

[Mary Haley]

Hi Elizabeth,

I was working on a plot to show the very issue that Rick pointed out.  He's
right that the data is pretty sparse.

Here's a modified version of your script that zooms in on the map a little,
and draws filled dots in red where the data is missing, and in black
otherwise.  You can see that each valid point is surrounded by missing
points.

I had to zoom in on the map because the data is so dense.

--Mary


On Thu, Aug 17, 2017 at 10:31 AM, Rick Brownrigg <brownrig at ucar.edu> wrote:

> Hi,
>
> I don't fully understand how the data are being computed, but the output
> file appears to be rather sparse, and that is likely the cause of the
> mottled appearance.  Attached is a "CellFill" version of the plot --
> CellFill more nearly shows the grid cells.
>
> And If I print sections of the ShowDays variable, its very typically like
> below; lots of missing-values interspersed with actual values.
>
> I'm not much help here, but hopefully this provides some insight...
> Rick
>
> 285,250)    -9999
> (286,0)    6.2
> (286,1)    -9999
> (286,2)    7.4
> (286,3)    -9999
> (286,4)     8
> (286,5)    -9999
> (286,6)    7.9
> (286,7)    -9999
> (286,8)    10.22222
> (286,9)    -9999
> (286,10)    8.7
> (286,11)    -9999
> (286,12)     9
> (286,13)    -9999
> (286,14)     8
> (286,15)    -9999
> (286,16)    10.1
> (286,17)    -9999
> (286,18)    8.4
> (286,19)    -9999
> (286,20)    11
> (286,21)    -9999
> (286,22)    8.454545
> (286,23)    -9999
> (286,24)    11.5
> (286,25)    -9999
> (286,26)    9.363636
> (286,27)    -9999
> (286,28)     9
> (286,29)    -9999
> (286,30)    9.5
> (286,31)    -9999
> (286,32)    9.272727
> (286,33)    -9999
> (286,34)    9.3
> (286,35)    -9999
> (286,36)    8.5
> (286,37)    -9999
> (286,38)    8.2
> (286,39)    -9999
> (286,40)    7.636364
> (286,41)    -9999
>
>
> On Thu, Aug 17, 2017 at 9:37 AM, Burakowski, Elizabeth <
> Elizabeth.Burakowski at unh.edu> wrote:
>
>> Hi ncl-talk,
>>
>>
>> I am trying to create a map showing the number of days with snow
>> depth greater than 200 mm from SNODAS files.  I have two scripts attached:
>>
>>
>> (1) subsetSNODAS_avgSNWDAYS.ncl
>>
>> - subsets a smaller region from nation SNODAS domain,
>>
>> - calculates the number of days with snow depth greater than user defined
>> threshold
>>
>> - calculates 2004-2017 average number of days with snow depth greater
>> than threshold
>>
>> - creates .nc file with 2004-2017 average
>>
>> I have uploaded a few .nc source SNODAS files that serve as input to the
>> subset script and the resulting 2004-2017 .nc file to the ncl-talk ftp
>> site.
>>
>>
>> (2) plotNESNODAS_snowdays.ncl
>>
>> - plots the output .nc file produced in subsetSNODAS_avgSNWDAYS.ncl
>>
>> - this is a separate script because the subset script takes a while to
>> run on the full time series for large regions.
>>
>>
>> Thanks,
>>
>>
>> Liz.
>>
>>
>>
>> Dr. Elizabeth A Burakowski
>> Research Assistant Professor
>> Earth Systems Research Center &
>> Institute for the Study of Earth, Oceans, and Space
>> University of New Hampshire
>> 8 College Road Durham, NH 03824
>> 603-862-1796 <(603)%20862-1796>
>> elizabeth.burakowski at unh.edu
>>
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>
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