Re: help with plotting a region within a GFS grib file

Yes .... FYI: You do not have to create a different variable.

http://www.ncl.ucar.edu/Document/Functions/Contributed/lonFlip.shtml

      printVarSummary( slp ) ; before lonFlip

      slp = lonFlip( slp )

      printVarSummary( slp ) ; after lonFlip

note the coordinate variables .... longitude [1-80 to +180]

West Africa might be something like

      latS = 5
      latN = 35
      lonW = -20
      lonE = 25
      slp(:,{latS:latN},{lonW:lonE}) ; coordinate subscripting

Sijikumar S wrote:
> Hi Erik,
> Map over West Africa crosses "Zero " degree longitude and reorder the
> longitude coordinate from "0 - 360" to "-180 -180" is a solution.
> Function "lonFlip" can do this.
> http://www.ncl.ucar.edu/Document/Functions/Contributed/lonFlip.shtml
>
>
> slp_flip=lonFlip(slp)
> lon2d_flip=slp_flip&lon_3
>
> mpres_at_mpMinLonF = lon2d_flip(145)
> ; select a subregion
> mpres_at_mpMaxLonF = lon2d_flip(215)
> mpres_at_mpMinLatF = lat2d(65)
> mpres_at_mpMaxLatF = lat2d(125)
>
>
> Siji
>
>
>
> On 9/26/07, *Erik Noble* <nobleeu_at_gmail.com <mailto:nobleeu_at_gmail.com>>
> wrote:
>
> Hi. I am trying to overlay several variables on a plot over aregion
> within a GFS file.
> The overlay part is easy.
>
> I am confused about why I am getting errors with plotting the map of
> the region (West Africa). My grid is 181 X 360.
>
> Why am I getting this error (Below)? Should not the gsn_csm_map_ce
> take care of this?
> Please help.
> -Erik
>
> Copyright (C) 1995-2007 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 4.3.1
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
> (0) Working on time: 08_07_2006 00 UTC
> (0) gsn_csm_map_ce: Fatal: The resources
> mpMinLonF/mpLeftCornerLonF must be less than the resources
> mpMaxLonF/mpRightCornerLonF.
> (0) Execution halted.
>
> My code:
> begin
> ;************************************************
> a = addfile("../FNL_SOP3_08_2006/fnl_060807_00_00.nc","r")
>
> lat2d = a->lat_3 ;
> lon2d = a->lon_3 ;
>
> time = "08_07_2006 00 UTC"
> type = "pdf"
> wks = gsn_open_wks(type,"FNL-08-07")
> gsn_define_colormap(wks,"BlAqGrYeOrRe") ; choose colormap
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> ; First get the variables we will need
>
> slp = a->PRMSL_3_MSL_10 ; slp (Pa)
> slp = slp/100 ;
> Turn Pressure into hPa
> slp_at_description = "Sea Level Pressure"
> slp_at_units = "hPa"
>
> tc2 = a->TMP_3_SFC_10 ; T (K) at surface (can be SST,
> too)
> tc2 = tc2-273.16
> tf2 = 1.8*tc2+32. ; Turn temperature
> into Fahrenheit
> tf2_at_description = "Surface Temperature"
> tf2_at_units = "F"
>
> ; Set some Basic Plot options
>
> mpres = True ; Create map background
> print("Working on time: " + time )
>
> mpres_at_gsnCenterString = "FNL Reanalysis" ; some titles
> mpres_at_gsnLeftString = "hPa"
> mpres_at_gsnRightString = "DegF" ; "~" is txFuncCode
> mpres_at_gsnCenterString = "Valid' + time'"
> mpres_at_gsnDraw = False ; don't draw
> mpres_at_gsnFrame = False ; don't
> advance frame
>
>
> mpres_at_mpGeophysicalLineColor = "Black"
> mpres_at_mpGeophysicalLineThicknessF = "3.0"
> mpres_at_mpGridLineColor = "Black"
> mpres_at_mpLimbLineColor = "Black"
> mpres_at_mpNationalLineColor = "Black"
> mpres_at_mpPerimLineColor = "Black"
> mpres_at_mpUSStateLineColor = "Black"
>
> mpres_at_lbOrientation = "Horizontal" ;
> vertical label bar
> mpres_at_lbLabelAutoStride = True ; optimal
> label stride
> mpres_at_gsnSpreadColors = True ;
> use full range of colors
>
> mpres_at_gsnAddCyclic = False
>
> mpres_at_mpCenterLonF = 0. ; center
> plot at 180
>
> mpres_at_mpMinLonF =
> lon2d(325) ; select a subregion
> mpres_at_mpMaxLonF = lon2d(35)
> mpres_at_mpMinLatF = lat2d(65)
> mpres_at_mpMaxLatF = lat2d(125)
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> ; First get the variables we will need
>
> slp = a->PRMSL_3_MSL_10 ; slp (Pa)
> slp = slp/100 ;
> Turn Pressure into hPa
> slp_at_description = "Sea Level Pressure"
> slp_at_units = "hPa"
>
> tc2 = a->TMP_3_SFC_10 ; T (K) at surface (can be SST, too)
> tc2 = tc2-273.16
> tf2 = 1.8*tc2+32. ; Turn temperature
> into Fahrenheit
> tf2_at_description = "Surface Temperature"
> tf2_at_units = "F"
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> ; Plotting options for SLP
>
> ;mpres_at_gsnContourLineThicknessesScale = 2.0
> mpres_at_cnLevelSelectionMode = "ManualLevels" ; set
> manual contour levels
> mpres_at_cnMinLevelValF = 900. ; set min
> contour level
> mpres_at_cnMaxLevelValF = 1110. ; set max
> contour level
> mpres_at_cnLevelSpacingF = 4 ; set contour
> spacing
> mpres_at_cnLineColor = "NavyBlue"
> mpres_at_cnHighLabelsOn = True
> mpres_at_cnLowLabelsOn = True
> mpres_at_cnLineLabelBackgroundColor = -1
> mpres_at_cnFillDrawOrder = "Predraw" ; areas before
> map gets
>
> ; Plotting options for T
> mpres2 = True
> mpres2_at_cnFillOn = True
> mpres2_at_cnMinLevelValF = -20. ; set
> min contour level
> mpres2_at_cnMaxLevelValF = 90. ; set max
> contour level
> mpres2_at_cnLevelSpacingF = 5
> mpres2_at_gsnSpreadColorEnd = -3 ; End third from the last color
> in color map
>
> ; MAKE PLOTS
> plot = gsn_csm_contour_map_overlay(wks,slp,tf2,mpres,mpres2)
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> end
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Received on Thu Sep 27 2007 - 07:56:26 MDT