Re: Masking data lying outside polyline

Use the function:
http://www.ncl.ucar.edu/Document/Functions/Built-in/gc_inout.shtml

Some examples of usage:

http://www.ncl.ucar.edu/Applications/shapefiles.shtml
Examples 4, 5, 8

http://www.ncl.ucar.edu/Applications/mask.shtml
Example 9

Good luck

On 3/7/12 2:37 AM, Abhishek Gupta wrote:
> *I am using following program to plot contour using sfxarray . I do not want to draw contour out side polyline .which function should i used to masking data outside polyline.*
>
>
> ; Example script to produce plots for a WRF real-data run,
> ; with the ARW coordinate dynamics option.
> ; Script show how to zoom into a given area
>
> load"$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load"$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
> ;load"./WRFUserARW.ncl"
> load"$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>
> begin
>
>
> ; Read the file
> ;************************************************
>
> lm=asciiread("lower_yamuna.prn",-1,"string")
> um=asciiread("upper_yamuna.prn",-1,"string")
> bt=asciiread("sahibi.prn",-1,"string")
> ; d1=asciiread("d1.prn",-1,"string")
>
> delim =" "
> nfields = str_fields_count(lm(1), delim)
> print(nfields)
> print(lm(1))
>
> lm_lat =stringtofloat(str_get_field(lm,nfields,delim))
> um_lat =stringtofloat(str_get_field(um,nfields,delim))
> bt_lat =stringtofloat(str_get_field(bt,nfields,delim))
>
> lm_lon =stringtofloat(str_get_field(lm,nfields-1,delim))
> um_lon =stringtofloat(str_get_field(um,nfields-1,delim))
> bt_lon =stringtofloat(str_get_field(bt,nfields-1,delim))
>
>
> ;***************************************************
> ;Read the input.csv file
>
> data=asciiread("input.csv",-1,"float")
>
> dim_lm=dimsizes(data)/3
> lon=new((/dim_lm/),"float")
> lat=new((/dim_lm/),"float")
> rh=new((/dim_lm/),"float")
>
>
> do i=0,dimsizes(data)-1,3
> lat(i/3)=data(i)
> end do
> do i=1,dimsizes(data)-1,3
> lon(i/3)=stringtofloat(data(i))
> end do
>
> do i=2,dimsizes(data)-1,3
> rh(i/3)=stringtofloat(data(i))
> end do
>
> print(lat)
> print(lon)
> print(rh)
>
> ; For CSV file file following method is used
>
> ; delim =","
> ;nfields = str_fields_count(lm(1), delim)
> ;print(nfields)
> ;print(lm(1))
>
> ;name =str_get_field(lm,nfields-3,delim)
>
> ; lat =stringtofloat(str_get_field(lm,nfields-2,delim))
>
> ; lon =stringtofloat(str_get_field(lm,nfields-1,delim))
>
> ; rh = stringtofloat(str_get_field(lm,nfields,delim))
>
>
> k=0
>
> do i=0,dimsizes(lat)-1
>
> if (.not.any(ismissing(rh(i)))) then
>
> rh(k)=rh(i)
>
> lon(k)=lon(i)
>
> lat(k)=lat(i)
>
>
> k=k+1
>
> end if
>
> end do
> ;******************************************************
> ;save station name,lat ,lon,rainfall values into an array.
>
> rhn=new(k,float)
> lond=new(k,float)
> latd=new(k,float)
>
> do i=0,k-1
>
> rhn(i)=stringtofloat(rh(i))
> lond(i)=stringtofloat(lon(i))
> latd(i)=stringtofloat(lat(i))
> end do
>
> print(rhn)
> print(lond)
> print(latd)
> ;********************************************************
>
> ;setting some plotting option& contour plot.
>
> wks = gsn_open_wks("pdf","contour")
>
> colors = (/"white","black","white","yellow","yellowgreen","forestgreen","deepskyblue","royalblue4","darkorange3","red" /)
>
> gsn_define_colormap(wks,colors)
>
>
> res = True
> res@gsnMaximize = True
> res@gsnDraw=False
> res@gsnFrame=False
> res@cnLevelSelectionMode ="ExplicitLevels" ; set explicit contour levels
> res@cnLevels = (/1.,10.,20.,40.,70.,130.,200./)
> res@cnFillOn =True
> res@cnLinesOn =False;True
> res@cnFillMode ="AreaFill"
> res@cnSmoothingOn =True
> ; res@cnSmoothingDistanceF =.0000001
> ; res@cnSmoothingTensionF =5.5
> ; res@cnMaxPointDistanceF =0
> ; res@cnFillScaleF = 9
>
> res@mpProjection ="Mercator" ; Change the map projection.
> ; res@cnRasterSmoothingOn =True
> res@lbLabelAutoStride = True
> res@lbBoxLinesOn = False
> res@tiMainString ="Mahanadi Basin (Rainfall in mm)"
> res@gsnAddCyclic=True; False
> ; res@tfDoNDCOverlay=True
> res@sfXArray = lond
> res@sfYArray = latd
>
> res@mpLimitMode ="LatLon" ; Change the area of the map
> res@mpMinLatF = 27.0 ; viewed.
> res@mpMaxLatF = 31.5
> res@mpMinLonF = 75.5
> res@mpMaxLonF = 78.8
>
> ; res@mpLimitMode ="Corners"
> ;res@mpLeftCornerLatF =23;min(lm_lat)-.1;min(latd)-.1;lat2d(20,18)
> ;res@mpLeftCornerLonF =72;min(um_lon)-.1;min(lond)-1.9 ;lon2d(20,18)
> ;res@mpRightCornerLatF =35;max(um_lat)+.1;max(latd)+.3; lat2d(58,52)
> ;res@mpRightCornerLonF =90;max(lm_lon)+.1;max(lond)+.3;lon2d(58,52)
>
> res@mpOutlineDrawOrder ="PostDraw"
> res@mpFillDrawOrder ="PreDraw"
> res@pmTickMarkDisplayMode ="Always"
> plot = gsn_csm_contour_map(wks,rhn,res)
> ; plot = gsn_csm_contour_map_ce(wks,rhn,res)
>
> ;*********************************************************************
> ; Now add some markers to show where the original 1D points are.
> ;
> ;mkres = True
> ;mkres@gsMarkerIndex = 16 ; Filled dots
> ; mkres@gsMarkerSizeF = .001
> ;dum = gsn_add_polymarker(wks,map,lond,latd,mkres)
>
> ;*******************************************************
> ;draw basin bounadry
>
> ; draw basin bounadry
>
> poly_res=True
> ; poly_res@gsLineColor="Red"
> poly_res@gsLineThicknessF=2.5
>
>
>
> plot1=gsn_add_polyline(wks,plot,lm_lon,lm_lat,poly_res)
> plot2=gsn_add_polyline(wks,plot,um_lon,um_lat,poly_res)
> plot3=gsn_add_polyline(wks,plot,bt_lon,bt_lat,poly_res)
>
>
>
> txres = True
> txres@txFontHeightF = 15;fheight ; Set the font height
> ; txres@txConstantSpacingF=1.2
>
> ; gsn_text_ndc(wks,"Sub basin wise Average Rainfall Forecast",.4,.27,txres)
>
> delete(txres)
> txres = True
> txres@txFontHeightF = 12;fheight ; Set the font height
> ; txres@txConstantSpacingF=1.2
>
> plot9=gsn_add_text(wks,plot,"Lower Yamuna",77.2,29,txres)
> plot9=gsn_add_text(wks,plot,"Upper Yamuna",77.7,31,txres)
> plot9=gsn_add_text(wks,plot,"Sahibi",76.7,28,txres)
>
> draw(plot)
> frame(wks)
>
>
> end
>
>
> --
> Abhishek Kumar Gupta,
> Junior Research Fellow,
> India Meteorological Department,
> Lodi Road ,New Delhi-110003,
> India
>
>
>
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Received on Wed Mar 7 04:13:21 2012