[ncl-talk] Sub: ESMF_ Regrid...

[Mary Haley]

To ncl-talk,

This discussion was taken offline at the NCL workshop. The data being
passed to the regridding routine was calculated incorrectly, and hence the
regridded results were also incorrect.  The second issue was that the
source lat/lon grid was not being defined properly.

These issues were fixed and now the regridding is working as expected.

--Mary


On Mon, Feb 8, 2016 at 9:30 PM, Adv <advita6 at gmail.com> wrote:

> Hi NCL users,
> I have printed below the program I use to plot a figure attached here. I
> doubt whether the regrid function works or not? Because, the figure looks
> so weird. Could someone help me to fix this bug?
>
> Thank you
> Adv
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/esmf/ESMF_regridding.ncl"
> begin
> ;a = (/1,2,3,4,5,6,7,8/)
> ;a0 = onedtond(a,(/4,2/))
> ;print(a0)
> ;printVarSummary(a0)
> ;return
> strll  = asciiread("stationmac.txt", -1, "string") ;
>   print(strll)   ; STATION","STATION_NAME", "LAT", "LON"
>   print("=====")
>
> sloc = str_get_field(strll , 2, ",")
>   lat  = tofloat( str_get_field(strll , 3, ",")  )
>   lon  = tofloat( str_get_field(strll , 4, ",")  )
>   print(sloc +" : "+lat+" "+lon)
> print(lon)
> ;&&&&&&&&&&&
> lonm=lon(0:389)
> latm=lat(0:389)
> ;minlat=min(latm)
> ;minlon=min(lonm)
> ;maxlat=max(latm)
> ;****************
> mlon = 390
> dlon = -90.35 / mlon
> lonn  = fspan (-116.1, (mlon - 1) * dlon, mlon)
> mlat = 390
> dlat = 49.0 / mlat
> latt  = fspan (40.00, (mlat - 1) * dlat, mlat)
> print(lonn)
> minlat=min(latt)
> minlon=min(lonn)
> maxlat=max(latt)
> maxlon=max(lonn)
> diri="/home/dailysimms/prec-obs/"
> z1 = asciiread(diri+"prec_avg_Jan-Dec1965-2005",-1,"float")
> print(z1)
> printVarSummary(z1)
> z0 = onedtond(z1,(/390,390/))
> print(z0)
> printVarSummary(z0)
> z0!0="lat"
> z0!1="lon"
> z0&lat=latm
> z0&lon=lonm
> printVarSummary(z0)
> ;print(z0)
> ;print(min(z0)-min(z1))
> ;print(max(z0)-max(z1))
> print(min(z0))
> print(max(z0))
> ;ESMF REGRID *******************
> ;---Set up options for regridding to 0.1 degree grid
>   Opt                 = True
>
>   Opt at SrcGridLat      = latm
> Opt at SrcGridLon      = lonm
> ;---If you don't set these two, the regridding will be VERY slow
>   Opt at DstLLCorner     = (/floor(minlat)-0.1,floor(minlon)+0.1/)
>   Opt at DstURCorner     = (/ ceil(maxlat)-0.1, ceil(maxlon)+0.1/)
>   Opt at DstGridType     = "0.1deg"                ; destination grid
>   Opt at ForceOverwrite  = True
> ;  Opt at SrcGridMask    = where(.not.ismissing(z0),1,0)
>
>   Opt at Debug           = True
>   Opt at InterpMethod    = "bilinear"
>   pwv_regrid_p = ESMF_regrid(z0,Opt)
>   printVarSummary(pwv_regrid_p)
> ;---Plotting section
>  wks = gsn_open_wks("pdf","ESMF_regrid")
> gsn_define_colormap(wks,"rainbow")             ; Change color map
>
> ;---Resources to share between both plots
>     res                     = True              ; Plot modes desired.
>
>     res at gsnMaximize         = True              ; Maximize plot
>
>     res at gsnDraw             = False
>     res at gsnFrame            = False
>
>     res at cnFillOn            = True              ; color plot desired
>     res at cnLinesOn           = False             ; turn off contour lines
>     res at cnLineLabelsOn      = False             ; turn off contour labels
>     res at cnFillMode          = "RasterFill"      ; turn raster on
> ;    res at cnLevelSelectionMode = "ExplicitLevels"
> ;    res at cnLevels             = ispan(270,300,2)
>   res at mpFillOn                    = False
> res at mpLimitMode           = "LatLon"
>   res at mpMinLatF             =   40.
>   res at mpMaxLatF             =   49.
> res at mpMinLonF             = -116
>   res at mpMaxLonF             =  -90.1
>  res at mpFillOn            = False
>
>     res at trGridType          = "TriangularMesh"  ; allow missing
> coordinates
>     res at gsnAddCyclic        = False
>
>     res at lbLabelBarOn        = False
>
>     res at gsnAddCyclic        = False
> ;---Draw US states in a light gray
>   res at mpOutlineBoundarySets       = "GeophysicalAndUSStates"
>   res at mpUSStateLineColor          = "Gray10"
>
>   res at tiMainString                = "GPS PWV (18Z) (original)"
> res at tiMainString  = "Regridded to 0.1 deg using 'patch'"
>   map_regrid_p = gsn_csm_contour_map(wks,pwv_regrid_p,res)
> pres                    = True
>   pres at gsnPanelLabelBar   = True
>  pres at pmLabelBarWidthF   = 0.7
>   pres at gsnMaximize        = True
>   pres at lbBoxLinesOn       = False
>   pres at lbLabelFontHeightF = 0.01
>
>   gsn_panel(wks,(/map_regrid_p/),(/1,1/),pres)
> end
>
>
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