[ncl-talk] stat_despersion
ali mughal
mughalali655 at gmail.com
Thu Jul 1 01:33:27 MDT 2021
Thanks for the reply
shouldn't this
grid_stats(68,160,:) = stat_dispersion( ta(:,68,160), opt)
be changed to
grid_stats(68,160,3) = stat_dispersion( ta(:,68,160), opt)
to obtain the 10th Percentile ?
when I do it I get the following error
fatal:VarVarWrite: Number of dimensions on left hand side does not match
right hand side
fatal:["Execute.c":8576]:Execute: Error occurred at or near line 41
On Thu, Jul 1, 2021 at 3:27 PM Muhammad Omer Mughal <
m.mughal1 at graduate.curtin.edu.au> wrote:
> Ali
> This was a suggestion.
>
>
>
>
>
> ------------------------------
> *From:* Muhammad Omer Mughal <m.mughal1 at graduate.curtin.edu.au>
> *Sent:* Thursday, 1 July 2021 3:22 PM
> *To:* ali mughal <mughalali655 at gmail.com>; Buzan, Jonathan <
> jbuzan at purdue.edu>
> *Cc:* Ncl-talk <ncl-talk at ucar.edu>
> *Subject:* Re: [ncl-talk] stat_despersion
>
> I used the following script . I also copied the result at the end of the
> script. Can it be due to the reason that the value is too small
>
>
> a=addfile("BEM_April","r")
> ta_mean_BEM=a->TA_MEAN
> ta=ta_mean_BEM(24:719,0,:,:)
> ta=ta-273.16
>
> opt=False
> nlat=dimsizes(nlat1)
> mlon=dimsizes(mlon1)
> grid_stats = new ((/nlat,mlon,30/), typeof(ta), getFillValue(ta))
> grid_stats(68,160,:) = stat_dispersion( ta(:,68,160), opt)
> printMinMax (grid_stats, False)
>
> (0) Robust Dispersion Statistics: min=-0.552326 max=696
>
>
>
> ------------------------------
> *From:* ncl-talk <ncl-talk-bounces at mailman.ucar.edu> on behalf of Buzan,
> Jonathan via ncl-talk <ncl-talk at mailman.ucar.edu>
> *Sent:* Thursday, 1 July 2021 2:24 PM
> *To:* ali mughal <mughalali655 at gmail.com>
> *Cc:* Ncl-talk <ncl-talk at ucar.edu>
> *Subject:* Re: [ncl-talk] stat_despersion
>
> Hello,
>
> You should try 1 grid cell first and print the values and print the
> stat_dispersion, and double check that you are feeding the array the
> correct data.
>
> -Jonathan
>
>
>
> On Jul 1, 2021, at 5:52 AM, ali mughal via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
> Sorry a correction to the above email is that all values in grid_stats,
> tenthP and nintythP are 0.
>
> On Thu, Jul 1, 2021 at 11:49 AM ali mughal <mughalali655 at gmail.com> wrote:
>
> Dear All
>
> Here is how I have modified the code according to your suggestions.
> However, I am getting all values in the output of grid_stats.and when I try
> plotting the tenth percentile I also have a zero value. I will be
> extremely grateful for your support.
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> a=addfile("wrfout","r")
> ta_mean_BEM=a->TA_MEAN
> ta=ta_mean_BEM(24:719,0,:,:)
> ta=ta-273.16
> nlat1=ta(0,:,0)
> mlon1=ta(0,0,:)
>
>
> nlStrt=0
> nlLast=129
> mlStrt=0
> mlLast=210
> nlat=dimsizes(nlat1)
> mlon=dimsizes(mlon1)
>
> grid_stats = new ((/nlat,mlon,30/), typeof(ta), getFillValue(ta))
> do nl=nlStrt,nlStrt-1
> do ml=mlStrt,mlStrt-1
>
> grid_stats(nl-nlStrt,ml-mlStrt,:) = stat_dispersion( ta(:,nl,ml),
> opt)
>
> end do
> end do
>
> tenthP=grid_stats(:,:,3)
>
> nintythP=grid_stats(:,:,13)
>
>
> type = "png"
> wks = gsn_open_wks(type,"abc")
> res =True
> opts = res
> opts at cnFillOn = True
> opts at cnConstFEnableFill = True
> opts at cnConstFLabelBackgroundColor = "transparent"
>
>
> pltres = True
> pltres at NoTitles = True
> pltres at gsnMaximize = True
> pltres at FramePlot = False
> pltres at PanelPlot = True
> mpres = True
> mpres at mpOutlineBoundarySets ="NoBoundaries"
> contour_lh = wrf_contour(a,wks,tenthP,opts)
> delete(opts)
>
> plot = wrf_map_overlays(a,wks,(/contour_lh/),pltres,mpres)
> draw(plot)
> frame(wks)
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Wed, Jun 30, 2021 at 10:24 PM Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
> Also, stat_dispersion returns an array of 30 values each time, not a
> single value. See function documentation. So you need to add an extra
> dimension in the loop calculation, like this:
>
> grid_stats = new ((/ nlat, mlon, 30 /), typeof(rf), getFillValue(rf))
>
> do ...
> do ...
> grid_stats(nl-nlStrt,ml-mlStrt,:) = stat_dispersion( rf(:,nl,ml),
> opt)
> end do
> end do
>
> When the loop is complete, the 10th percentile values will be in
> grid_stats(:,:,3), which is a 2-D grid that you can plot. The 90th
> percentile values will be in grid_stats(:,:,13). Again, refer to the
> function documentation for the correct index values to access the desired
> statistics.
>
>
> On Wed, Jun 30, 2021 at 5:13 AM Buzan, Jonathan <jbuzan at purdue.edu> wrote:
>
> NCL counts from 0 to n-1, not from 1 to n. So your loop vars need to
> account for that.
>
> Cheers,
> -Jonathan
>
> On Jun 30, 2021, at 1:10 PM, ali mughal via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
> Dear community
> Thank you very much for your helpful comments.
> As an initial test, I was trying to obtain statistics at all grid points
> before plotting them. I used the following code
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> a=addfile("wrfout","r")
> ta_mean_BEM=a->TA_MEAN
> ta=ta_mean_BEM(24:719,0,:,:)
> rf=ta-273.16
> nlat1=rf(0,:,0)
> printVarSummary(nlat)
> mlon1=rf(0,0,:)
> printVarSummary(mlon)
> printVarSummary(rf)
> opt=False
>
> nlStrt=0
> nlLast=129
> mlStrt=0
> mlLast=210
> nlat=dimsizes(nlat1)
> mlon=dimsizes(mlon1)
>
> grid_stats = new ((/nlat(0),mlon(0)/), typeof(rf), getFillValue(rf))
> printVarSummary(grid_stats)
> do nl=0,nlLast
> do ml=0,mlLast
>
> grid_stats(nl-nlStrt,ml-mlStrt) = stat_dispersion( rf(:,nl,ml),
> opt)
>
> end do
> end do
>
> copy_VarCoords(rf(:,nlStrt:nlLast,mlStrt:mlLast), grid_stats)
> grid_stats at long_name = "stat_dispersion at individual grid points"
> printVarSummary(grid_stats)
>
> But I obtain the following output from my print statements and the errors
>
> Variable: rf
> Type: float
> Total Size: 75418560 bytes
> 18854640 values
> Number of Dimensions: 3
> Dimensions and sizes: [696] x [129] x [210]
> Coordinates:
>
> Variable: grid_stats
> Type: float
> Total Size: 108360 bytes
> 27090 values
> Number of Dimensions: 2
> Dimensions and sizes: [129] x [210]
> Coordinates:
> fatal:VarVarWrite: Number of dimensions on left hand side does not match
> right hand side
> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 46 in
> file var_Test.ncl
>
> fatal:Subscript out of range, error in subscript #1
> fatal:An error occurred reading rf
> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 51 in
> file var_Test.ncl
>
> Variable: grid_stats
> Type: float
> Total Size: 108360 bytes
> 27090 values
> Number of Dimensions: 2
> Dimensions and sizes: [129] x [210]
> Coordinates:
> Number Of Attributes: 1
> long_name : stat_dispersion at individual grid points
>
>
> On Wed, Jun 30, 2021 at 12:01 AM Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
> Ali, you do not need to make new code to find the 10th and 90th percentile
> values. Just use stat_dispersion directly, and take only the output values
> that you need. The function is designed to be used in this way. There is
> no significant performance impact from ignoring all the other result values.
>
> You can easily make a spatial map of 10th or 90th percentile values. Just
> call stat_dispersion inside a double loop over X and Y dimensions.
>
>
> On Tue, Jun 29, 2021 at 9:23 AM Buzan, Jonathan via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
> Hello,
>
> I’ve used that function a bunch. If you only want 10th and 90th
> percentile, you’ll want to use:
>
> qsort
> Which will sort your data within a single grid cell from lowest to highest.
>
> And then grab the specific lines of code for 10th and 90th percentiles
> from the stat_dispersion function in:
> $NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl
>
> If you look at the function, you’ll see that it uses qsort, then goes step
> by step through calculating all the different applications.
>
> Cheers,
> -Jonathan
>
> On Jun 29, 2021, at 5:14 PM, ali mughal via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
> Dear NCL community
>
> In the following ncl function
>
>
> http://www.ncl.ucar.edu/Document/Functions/Contributed/stat_dispersion.shtml
>
> Is it possible to use 10th and 90th percentile values only ?
>
> Also can these values be used to develop a spatial map?
>
> For example if I want to find the 10th and 90th percentile of air
> temperature within the urban grid cells only.
>
> Can anyone share an example script or point me to any web resource will be
> appreciated.
>
> Thanks in advance
>
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