[ncl-talk] contour not working with missing values in coordinate variables

Mon Dec 21 17:43:12 MST 2020

Having missing "coordinates"  [eg: latitude, longitude, level, time, etc]
is not recommended by the netCDF user group.
A missing value associated with one or more missing coordinates makes no
sense.

It is the users responsibility to explore the data.explore.

%> ncdhump -h   ...   | less
or
%> ncl_filedump ... | less

The attached script does that

[1] the full (800,1600) array for different variables
     NCL can not plot or attempt to plot data if there are no valid
coordinates.

[2] then the subset you specified. If you extract just the sub region you
specified the varble and, more importantly, the latitude/longitudes have no
missing values. This can be plotted by associating the subset region
latitude & longitudes to the variable.

Carefully look at the printed output to see what is happening

[3] Hopefully, you will be able to use the attached approach to work with
the WRF data.

[4] Please submit clean scripts. Following heavily commented scripts is
annoying and time consuming.

Stay Healthy

Merry Christmas

%> ncl ncl XiaomingHu_1.ncl

On Mon, Dec 21, 2020 at 12:35 PM Barry Lynn via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Hi:
>
> If the nc data appears to be upside down, when you plot it, you probably
> need to subtract 90 degrees from your data.
>
> Also, you should printMinMax(data, False) to see the bounds of the data
> you are trying to plot. If the longitude is not -180 to 180, this could
> also mess up your program.
>
> Barry
>
>
>
> On Mon, Dec 21, 2020 at 8:38 PM xiaoming Hu <yuanfangcan at hotmail.com>
> wrote:
>
>> Thanks!
>> Not quite.
>> What I currently plot is
>> But I would like to plot the full data (from ncveiw):
>> ncview figure appears to be up-side-down.
>> Thanks
>> Xiaoming
>> ------------------------------
>> *From:* Barry Lynn <barry.h.lynn at gmail.com>
>> *Sent:* Monday, December 21, 2020 12:27 PM
>> *To:* xiaoming Hu <yuanfangcan at hotmail.com>
>> *Cc:* ncl-talk <ncl-talk at ucar.edu>; Xiaoming Hu <xhu at ou.edu>
>> *Subject:* Re: [ncl-talk] contour not working with missing values in
>> coordinate variables
>>
>> Hello:
>>
>> You can always plot point data, interpolating it to a grid.
>>
>> Perhaps this will help...?
>>
>> https://www.ncl.ucar.edu/Document/Functions/Built-in/linint2_points.shtml
>>
>> On Mon, Dec 21, 2020 at 7:44 PM xiaoming Hu via ncl-talk <
>> ncl-talk at mailman.ucar.edu> wrote:
>>
>> Because there are missing values in the 2d latitude and longitude,  the
>> contour plot did not work.
>> So I have to cut off the area with the missing coordinate variables by
>>   LST = f->visible_count(78:730,365:998)
>>   LST at lat2d = latitude(78:730,365:998)
>>   LST at lon2d = longitude(78:730,365:998)
>>
>> But by doing so, I miss a lot of useful data.
>> Anyway to plot the full data?   My full script is attached
>> A sample data file:
>> http://www.caps.ou.edu/micronet/SouthernOcean/Observation/satellite.SATCORPS_V2.2_HIMAWARI-8.2km.201802170000.NC
>> The domain I want to plot on:
>> http://www.caps.ou.edu/micronet/SouthernOcean/Observation/wrfout_d01_2018-02-18_20:00:00
>> BTW: this script works very slow even when I cut off the area with
>> missing coordinate.
>> Thanks a lot!
>> Xiaoming Hu
>> _______________________________________________
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>>
>>
>> --
>> Guest Editor of Special Issue “Extreme Hydroclimatic Events and
>> Prediction”
>> LINK:
>>
>> https://www.mdpi.com/journal/water/special_issues/Extreme_Hydroclimatic_Events
>>
>> Barry H. Lynn, Ph.D
>> Senior Associate Scientist, Lecturer,
>> The Institute of the Earth Science,
>> The Hebrew University of Jerusalem,
>> Givat Ram, Jerusalem 91904, Israel
>> Tel: 972 547 231 170
>> Fax: (972)-25662581
>>
>> C.E.O, Weather It Is, LTD
>> Weather and Climate Focus
>> http://weather-it-is.com
>> Jerusalem, Israel
>> Local: 02 930 9525
>> Cell: 054 7 231 170
>> Int-IS: x972 2 930 9525
>>
>>
>
> --
> Guest Editor of Special Issue “Extreme Hydroclimatic Events and Prediction”
> LINK:
>
> https://www.mdpi.com/journal/water/special_issues/Extreme_Hydroclimatic_Events
>
> Barry H. Lynn, Ph.D
> Senior Associate Scientist, Lecturer,
> The Institute of the Earth Science,
> The Hebrew University of Jerusalem,
> Givat Ram, Jerusalem 91904, Israel
> Tel: 972 547 231 170
> Fax: (972)-25662581
>
> C.E.O, Weather It Is, LTD
> Weather and Climate Focus
> http://weather-it-is.com
> Jerusalem, Israel
> Local: 02 930 9525
> Cell: 054 7 231 170
> Int-IS: x972 2 930 9525
>
> _______________________________________________
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