# [ncl-talk] smops interpolation

Dennis Shea shea at ucar.edu
Fri Sep 7 09:55:14 MDT 2018

```[1] No
[2] Yes

nlat = 720
latitude = *fspan*(-49.875, 49.875, nlat)
latitude at units = "*degrees_north*"
latitude at long_name = "latitude"
latitude!0        = "latitude"
latitude&latitude =  latitude

printVarSummary(latitude)
printMinMax(latitude,0)

mlon = 1440
longitude  = *lonGlobeFo*
<https://www.ncl.ucar.edu/Document/Functions/Contributed/lonGlobeFo.shtml>(mlon,
"longitude", "longitude", "degrees_east")  ; 0->360
longitude  = (/ longitude - 180. /)  ; subtract 180 from all values
longitude&longitude = longitude            ; update coordinates
printVarSummary(lon)

printVarSummary(longitude)
printMinMax(longitude,0)

x = *short2flt*
<https://www.ncl.ucar.edu/Document/Functions/Contributed/short2flt.shtml>(
f->Blended_SM )

x&latitude = latitude
x&longitude = longitude

printVarSummary(x)

[3]/[4]

xo = .... longitudes of land points...

yo = ... latitudes ....

xpts = *linint2_points*(x&longitude,x&latitude,x, False, xo,yo, 0)

printVarSummary(xpts)

printMinMax(xpts,0)

On Tue, Sep 4, 2018 at 5:50 AM, Ehsan Taghizadeh <ehsantaghizadeh at yahoo.com>
wrote:

> I did your comments, however I encountered some difficulties and I'll be
> thankful if I could have any help about them, too.
>
> 1. Should I change
>
> latitude = *fspan*(-49.875, 49.875, nlat)
>
> to
>
> latitude = *fspan*(-89.875, 89.875, nlat)
>
> or like longitude, use
>
> lat  = *latGlobeFo*(nlat, "lat", "latitude", "degrees_north")
>
>
> 2. Should I change
>
> latitude at units = "degrees_east"
>
> to
>
> latitude at units = "degrees_north"
>
>
> 3. How should I control FillValue (-999s), because after running ncl
> script, it writes -0.1 for Nan value of the data, both in grided and
> interpolated output files.
> 4. However the most difficulty is the interpolating part, because all
> interpolated values for all station points got -0.1, means Nan. There is no
> I've attached the output of interpolated file. I'll be thankful for any
> help.
>
> Sincerely
> Ehsan
>
> On Friday, August 31, 2018, 6:14:53 PM GMT+4:30, Dennis Shea <
> shea at ucar.edu> wrote:
>
>
> Sometimes, you have to read documentation associated with the file(s)
> *Soil Moisture* Operational Products System (*SMOPS*)
>
> The file has:
>
> netcdf NPR_SMOPS_CMAP_D20170410 {
> dimensions:
>
> *        Longitude = 1440 ;        Latitude = 720 ;*
> variables:
>         *short* Blended_SM(*Latitude, Longitude*) ;
>                 Blended_SM:long_name = "Blended Soil Moisture" ;
>                 Blended_SM:units = "m^3/m^3" ;
>                 Blended_SM:FillValue = -999s ;
>                 Blended_SM:valid_range = 0s, 10000s ;
>                 Blended_SM:*scale_factor *= 0.0001f ;
>
> [SNIP]
>                 :Product_Resolution = "0.25 degree" ;
>                 :Date_Start = "20170410" ;
>                 :Date_End = "20170410" ;
> [SNIP]
>  ====
> It does not have Latitude[*] and Longitude[*] coordinates. However,
> **you** can create them. Then, use ESMF or (say)* linint2_Wrap *
> <https://www.ncl.ucar.edu/Document/Functions/Contributed/linint2_Wrap.shtml>or
> *linint2_points_Wrap*
> <https://www.ncl.ucar.edu/Document/Functions/Contributed/linint2_points_Wrap.shtml>
> to perform the interpolation.
>
> ====
>
>       nlat = 720
>       latitude = *fspan*(-49.875, 49.875, nlat)
>       latitude at units = "degrees_east"
>       latitude at long_name = "latitude"
>       latitude!0        = "latitude"
>       latitude&latitude =  latitude
>
>       printVarSummary(latitude)
>       printMinMax(latitude,0)
>
>       mlon = 1440
>       longitude  = *lonGlobeFo* <https://www.ncl.ucar.edu/Document/Functions/Contributed/lonGlobeFo.shtml>(mlon, "longitude", "longitude", "degrees_east")  ; 0->360
>       longitude  = (/ longitude - 180. /)  ; subtract 180 from all values
>       longitude&longitude = longitude            ; update coordinates       printVarSummary(lon)
>
>       printVarSummary(longitude)
>       printMinMax(longitude,0)
>
>       x = *short2flt* <https://www.ncl.ucar.edu/Document/Functions/Contributed/short2flt.shtml>( f->Blended_SM )
>
>       x&latitude = latitude
>       x&longitude = longitude
>
>       printVarSummary(x)
>
>
>
> On Fri, Aug 31, 2018 at 5:45 AM, Ehsan Taghizadeh <
>
> Hi,
> Until now I've asked some questions related to interpolating some dataset
> on some unstructured points (synoptic stations). Now I have a new data set
> which I'm not sure about appropriate method to interpolating. I put one of
> my data (NPR_SMOPS_CMAP_D20170410.nc) in ftp.cgd.ucar.edu. I'll be
> thankful if some one could refer me to correct script, like on (https://www.ncl.ucar.edu/
> Applications/ESMF.shtml <https://www.ncl.ucar.edu/Applications/ESMF.shtml>)
> or (https://www.ncl.ucar.edu/ Applications/regrid.shtml
> <https://www.ncl.ucar.edu/Applications/regrid.shtml>), which interpolates
> my data on some special unstructured points.
> However the printVarSummary(Blended_SM) result is as below:
>
> Variable: Blended_SM
> Type: float
> Total Size: 4147200 bytes
>             1036800 values
> Number of Dimensions: 2
> Dimensions and sizes:   [Latitude | 720] x [Longitude | 1440]
> Coordinates:
> Number Of Attributes: 5
>   _FillValue :  1e+20
>   long_name :   Blended Soil Moisture
>   units :       m^3/m^3
>   FillValue :   -999
>   valid_range : (  0,  1 )
>
>
> Sincerely
> Ehsan
>
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