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

Hi and thank you to both.

Siji,
Thank you for pointing out the lonFlip command.

Dennis,
I need clarification...
My region is
 latS = -25
 latN = 35
 lonW = -35
 lonE = 25

If I use coordinate subscripting to call in my variable
slp(:,{latS:latN},{lonW:lonE})

do I still need to do all of the "selecting a subregion" part and if I
do, would the syntax below be correct?

lon2d_flip=slp&lon_3

               mpres_at_mpMinLonF = lon2d_flip({lonW})
      ; select a subregion
               mpres_at_mpMaxLonF = lon2d_flip({lonE})
               mpres_at_mpMinLatF = lat2d({latS)
               mpres_at_mpMaxLatF = lat2d({latN})

-Erik
On 9/27/07, Dennis Shea <shea_at_ucar.edu> wrote:
> 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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> >
> >
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Received on Thu Sep 27 2007 - 09:49:57 MDT