Plotting EASE grids

Hi there,

I regridded some ims data from 1024x1024 to EASE grid format, 721x721. The
NSIDC tool I used for the transform output the data in hexadecimal form so I
used ncl's stringtointeger tool to read it. I then used Dennis Shea's
EaseLatLon.nc coordinate file together with the ncl example ease_1.ncl to
try and plot the data, however my georeferencing seems to be off (please see
attached pdf).

I am trying to figure out if it is only a plotting/georeferencing problem or
does the error go deeper to the way I performed the grid transform.

Attached are the ncl script that reads and plots the data together with the
ouptput. Any suggestions you might have would be great.
Thanks, Gina.

-------------------------------------------------------------
begin

nlat=721
nlon=721

ims = fbindirread ("ims2008349.ease1",0,(/nlat,nlon/), "byte")
printVarSummary(ims)
;print(ims)

ims_int = stringtointeger(ims)
printVarSummary(ims_int)
;print(ims_int)

a = addfile("EaseLatLon.nc","r")

lat = a->latitude
lon = a->longitude

printVarSummary(lat)
printVarSummary(lon)

;*******************************************
; Create plots
;*******************************************

    wks = gsn_open_wks("ps","ims_ease1")
    gsn_define_colormap(wks,"amwg") ; Change color map

    res = True ; Plot modes desired.
    res@gsnMaximize = True ; Maximize plot
    res@gsnSpreadColors = True ; use full range of colormap
    res@cnFillOn = True ; color plot desired
    res@cnLinesOn = False ; turn off contour lines
    res@cnFillMode = "RasterFill" ; turn raster on
; res@pmLabelBarWidthF = 0.9 ; make wider
; res@pmLabelBarHeightF = 0.1 ; default is taller
; res@lbLabelFontHeightF = .018 ; default is HUGE

    res@cnLevelSelectionMode= "ExplicitLevels" ; set explicit contour levels
    res@cnLevels = (/48,49,50,51,52/) ;\
; ,5,253,254,255/)

;************************************************
;No georeferencing: simple contour. Draws faster
;************************************************
    res@tiMainString = "Ims 1024x1024 to EASE grid 721x721"
    plot = gsn_csm_contour(wks,ims_int,res) ; contour, no map

;*******************************************
; georeferencing: plot on polar projection
;*******************************************
                                             ; georeference
    ims_int@lat2d = lat
    ims_int@lon2d = lon

    res@trGridType = "TriangularMesh" ; allow missing coordinates

    res@gsnPolar = "NH" ; specify the hemisphere
    res@mpMinLatF = 35
    res@tiMainString = "gsn_csm_contour_map_polar"

    plot = gsn_csm_contour_map_polar(wks,ims_int,res)

end

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