[ncl-talk] Q about wind_stats function

[Rick Brownrigg]

I don't mind, but it really is best to post to the group, as there are many
more eyes/expertise that can potentially provide an answer. I mistakenly
did not cc the group in my original reply, and thus Dennis spent time
working on an answer because he hadn't seen mine.

To your specific question, I speculate that wspd and wdir are string
variables. You might try something like:

   wspd = string2float(str_get_field(data,1,delim))
   wdir = string2float(str_get_field(data,2,delim))

or stringtodouble() if you think that is warranted for your data.

Hope that helps...
Rick



On Mon, Jun 7, 2021 at 11:57 AM Li-Hao Young <lhy at umich.edu> wrote:

> Hi Rick,
>
> I hope you don’t mind that I’m taking the liberty to ask a follow-up
> question.
>
> I was able to successfully run the Example codes of wind_stats, and
> managed to read my wind speed and wind direction data (i.e., two columns in
> csv file) into NCL, using the following codes:
>
> diri = "./“
> fili = "2020Aug2021Apr.csv"
> delim  = ","
> data   = asciiread(diri+fili, -1, "string”)
> wspd = str_get_field(data,1,delim)
> wdir = str_get_field(data,2,delim)
>
> Using print(), I was able to see my data are correctly stored in “wspd”
> and “wdir".
> However, I could not figure out how to get the wind_stats to work on my
> data, as did the Example codes.
> The "x := wind_stats(wspd, wdir, 0, False)" does not work here, and showed
> another error message:
>
> fatal: Argument type mismatch on argument (0) of (wind_stats) can not
> coerce
> fatal: ["Execute.c":8635]
>
> Your assistance is much appreciated.
>
> Best,
> Li-Hao
>
>
> >
> > Hi Rick,
> >
> > Thanks for your prompt response.
> >
> > Your approach did solve the problem. Awesome, finally…:-)
> >
> > Best,
> > Li-Hao
> >
> >> On Jun 7, 2021, at 22:35, Rick Brownrigg <brownrig at ucar.edu> wrote:
> >>
> >> Hi,
> >>
> >> Yes, I see the same behavior too, and it is a bug. NCL requires
> functions/procedures to be defined before they are referenced, and in the
> file $NCLROOT/lib/ncarg/nclscripts/csm/contributed.ncl, that function
> "wind_stats" references "dim_avg_n_Wrap", which is not defined until later
> in the file.
> >> A solution that I verified works is to move the definition of
> "wind_stats" to the end of the contributed.ncl file. Kinda heavy handed,
> but it does solve the problem for your particular script.
> >>
> >> Hope that helps...
> >> Rick
> >>
> >>
> >> On Mon, Jun 7, 2021 at 7:39 AM Li-Hao Young via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
> >> Hi All at NCL-talk:
> >>
> >> My research requires me to obtain the standard deviation of wind
> direction. And this has led me to NCL's wind_stats function. Therefore, I
> have installed NCL 6.6.2 on my Mac Mojave (which took me many many
> hours...). However, while running the Example 1 codes of wind_stats from
> https://www.ncl.ucar.edu/Document/Functions/Contributed/wind_stats.shtml,
> I was stopped by a fatal error message and could not continue on with that
> example. The example codes are given at the bottom; the error occurred
> while executing "x := wind_stats(wspd, wdir, 0, False)" as follow:
> >>
> >> ncl 6>    x    := wind_stats(wspd, wdir, 0, False)  ; variable of type
> 'list'
> >> fatal:Undefined identifier: (dim_avg_n_Wrap) is undefined, can't
> continue
> >> fatal:["Execute.c":8637]:Execute: Error occurred at or near line 1442
> in file /usr/local/ncl-6.6.2/lib/ncarg/nclscripts/csm/contributed.ncl
> >>
> >> fatal:["Execute.c":8635]:Execute: Error occurred at or near line 6
> >>
> >> I have tried the Getting Started, documentation, archieves, etc., but
> could not resolve the problem as I have no experiences with NCL coding. I
> will very much appreciate it if someone could give me some pointers.
> >>
> >> Thanks,
> >> Young
> >>
> >> Example 1
> >>
> >>    N     = 10
> >>    u    :=
> >> random_normal
> >> (  0, 2, N)   ; zonal wind 'noise'
> >>    v    :=
> >> random_normal
> >> (-10, 2, N)   ; winds from the north
> >>    wspd :=
> >> wind_speed
> >> (u,v)
> >>    wdir :=
> >> wind_direction
> >> (u,v,0)
> >>
> >> print(sprintf("%7.2f", u)+sprintf("%7.2f", v)+sprintf("%7.2f",
> wspd)+sprintf
> >> ("%7.2f", wdir))
> >>
> >>    x    :=
> >> wind_stats
> >> (wspd, wdir, 0, False)  ; variable of type 'list'
> >>                           ; extract variables from list for clarity
> >>    wspd_avg = x[0]        ; average of 'wspd'
> >>    wspd_std = x[1]        ; standard deviation of 'wspd'
> >>    wdir_avg = x[2]        ; mean vector wind direction
> >>    wdir_std = x[3]        ; standard deviation of the wind direction
> >>    avgU     = x[4]        ; average zonal component
> >>    avgV     = x[5]        ; average medidional wind component
> >>
> >> delete
> >> (x)        ; no longer needed
> >>
> >>
> >> print(sprintf("%7.2f", wspd_avg)+sprintf
> >> ("%7.2f", wspd_std)  \
> >>         +
> >> sprintf("%7.2f", wdir_avg)+sprintf("%7.2f", wdir_std)  \
> >>         +sprintf("%7.2f", avgU )+sprintf("%7.2f", avgV ) )
> >>
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