[ncl-talk] Polymarker on lon/lat grid does not appear

Fri Oct 28 00:37:17 MDT 2016

Dear all,

I am trying to plot a dot (a station) in a map but the dot does not appear.
I looked into the archive search but could not find a solution. I attach the
relevant code below. I am not sure if the problem is a
map/transform/projection issue, an issue of Draw priority or simply NCL does
not know where to plot the dot (as the main plot coordinates are created
"dynamically"). The frustrating/interesting part is that with overlay
(ovelay countour lines to a basic countour map plot in another script) the
dot appears.

Here is the code (sorry for the length). Thank you for your time.

;================================================;

; horizontal contour plot with station

;================================================;

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

; ================================================;

begin

;=================================================;

; choose wks 

;=================================================;

nbeglon = (/-0.20/)

nbeglat = (/-0.2/) ; chooses begin of lon/lat(rotated coordinates of the
data)

nendlon = (/0.55/)

nendlat = (/0.58/)

starthour = 0

endhour   = 2      ;for three days

ndata     = 72

aa = starthour+1;

bb = endhour;

name = "1month"

PRM = "totDRE_surface" ;SOBS_RAD";"T_2M";

UNIT = "  [delta W/m^2]"

SCL1 = -2.6;2.5;.4;0.2 ;-0.5;-1

SCL2 = 2.6;2.5;.4;0.2  ;0.5;1

SCL3 = 0.2;0.05;0.25 ;0.1

IYR = 2013;

MON = "12" ; MONTH DEC OR JAN (01)

filename = ("winter."+IYR+"."+PRM+name+"")

;=================================================;

; choose level

;=================================================;

  lvl  = 39

;=================================================;

; open file and read in data, I cut this out as It does not matter

;=================================================;

;================================================;

; read in data    I cut this out as It does not matter

;================================================;

;vardumbs is the variable I'm going to countour (The basic countour plot to
which I want to add a dot)

dum1    = dim_avg_n(vardumbs,0)

plotvar = (dum1)   ; in ppb

aveplotvar = dim_avg_n(plotvar,0)   ;

aveplotvar2 = dim_avg_n(aveplotvar,0)

printVarSummary (plotvar)

printMinMax (plotvar, True)

delete(dum1)

  lat = f1[0]->lat({nbeglat:nendlat},{nbeglon:nendlon}) ;to retrieve lat 

  lon = f1[0]->lon({nbeglat:nendlat},{nbeglon:nendlon}) ;to retrieve lon

  nlat = dimsizes(lat)                                  ;this gives nlat=330

  nlon = dimsizes(lon)                                  ;this gives nlon=384

;================================================;

; Create wks according to definition

;================================================;

 wks   = gsn_open_wks ("png",filename)

;================================================;

; Define Colormap

;================================================;

cmap = (/"white","black","white","lemonchiffon1",\

        "lightblue1", "lightblue2","deepskyblue1","deepskyblue3","orchid3",\

        "darkorchid","blueviolet","darkorchid4","deeppink2"/)

gsn_define_colormap(wks,"temp_19lev")   ;meteoro

;===================================;

; Manage ressources and title

;===================================;

title = ""+PRM+" "+UNIT+""

tdate = "20.12.2013 - 21.1.2014 "

;================================================;

; Set some resources that will apply to the base

; contour/map plot 

;================================================;

 res                       = True

 res at tiMainString          = " "

 res at cnLevelSelectionMode  = "ManualLevels"                             ;
set manual contour levels

 res at lbLabelAngleF         = 45
; angle labels

 res at cnMinLevelValF        =  SCL1

 res at cnMaxLevelValF        =  SCL2

 res at cnLevelSpacingF       =  SCL3

 res at cnLabelBarEndStyle    =  "ExcludeOuterBoxes"

 res at cnFillPalette = "temp_19lev"   ;meteor

 res at gsnLeftString         = " "

 res at gsnRightString        = " "

;===============================================;

; standard stuff

;===============================================;

 res at gsnDraw                = False             ; Do not draw plot now
(helps adding stuff to the plot or producing labels etc)

 res at gsnFrame               = False             ; Do not advance frame

 res at cnFillOn               = True              ; color Fill

 res at cnFillMode             = "AreaFill"        ; raster mode

 res at cnRasterSmoothingOn    = True

 res at cnRasterMinCellSizeF   = 0.0005

 res at cnLinesOn              = True              ; Turn off contour lines

 res at cnLineLabelsOn         = False             ; Turn off label of contour
lines

 res at cnMaxLevelCount        = 100

 res at cnInfoLabelOn          = False             ; do not plot info label

 res at gsnAddCyclic           = False             ; data is not cyclic

 res at mpDataBaseVersion      = "MediumRes"       ; map resolution

 res at mpProjection           = "CylindricalEquidistant"

 res at mpOutlineBoundarySets  = "National"

 res at mpFillOn               = True

 res at mpPerimOn              = False

 res at mpMaskAreaSpecifiers   = (/"land"/)

 res at mpFillDrawOrder        = "PreDraw"

 res at mpGridAndLimbOn        = True             ; en- or disable lon lat
lines

 res at mpGeophysicalLineThicknessF = 2.5

 res at pmTickMarkDisplayMode  = "Always"

 res at tmXTMinorOn            = False

 res at tmYRMinorOn            = False

;=================================================;

; map projection

;=================================================;

  res at tfDoNDCOverlay        = True

  res at mpDataBaseVersion     = "HighRes"               ; map resolution

  res at mpProjection          = "CylindricalEquidistant"  ; map projection

  res at mpOutlineBoundarySets = "National"

  res at mpCenterLonF = lon({rlon|0},{rlat|0})

  res at mpCenterLatF = lat({rlon|0},{rlat|0})

  res at mpLimitMode = "Corners"

  res at mpLeftCornerLatF = lat(0,0)                     ; latitude left lower
corner from model output

  res at mpLeftCornerLonF = lon(0,0)                     ; longitude left lower
corner from model output

  res at mpRightCornerLatF = lat(nlat(0)-1,nlat(1)-1)    ; latitude right upper
corner from model output

  res at mpRightCornerLonF = lon(nlon(0)-1,nlat(1)-1)    ; longitutde right
upper corner from model output

  res at sfXCStartV = nbeglon                               ; minimal length
(rotated): embedd data into map

  res at sfXCEndV =  nendlon                                 ; maximal length
(rotated): embedd data into map

  res at sfYCStartV = nbeglat                               ; minimal length
(rotated): embedd data into map

  res at sfYCEndV = nendlat                                  ; maximal length
(rotated): embedd data into map

;=================================================;

; Scaling

;=================================================;

  res at vpWidthF  = 0.6                    ; change the aspect ratio

  res at vpHeightF = 0.6

  res at vpXF      = .1                     ; location of where plot starts

  ;res at vpYF      = 1

 bot_plot = gsn_csm_contour_map(wks,plotvar(:,:),res)

;-----------add polymarker-----------------;

  light_gray = NhlNewColor(wks,0.85,0.85,0.85)         ; Add light gray

mkres =True

thissio_lat = 0.2732

thissio_lon =0.1720

mkres at gsMarkerIndex = 17     ; Filled circle

  mkres at tfPolyDrawOrder = "PreDraw"

  mkres at gsMarkerSizeF = 0.03 

Station = gsn_add_polymarker(wks,bot_plot,thissio_lon,thissio_lat,mkres)

draw (bot_plot)

;*****************************************************   

; Manually create and attach titles

;*****************************************************   

;

; Attach some titles at the top.

;

  res_text               = True

  res_text at txFontHeightF = 0.03                       ; change font size

  txid_top = gsn_create_text(wks, title, res_text)

  amres                  = True

  amres at amJust           = "BottomCenter"

  amres at amParallelPosF   =  0.0    ; This is the center of the plot.

  amres at amOrthogonalPosF = -0.72   ; This is above the top edge of the plot.

  annoid_top = gsn_add_annotation(bot_plot, txid_top, amres)

  res_text at txFontHeightF = 0.02                       ; change font size

  txid_mid = gsn_create_text(wks, tdate,res_text)

  amres at amOrthogonalPosF = -0.62  ; This is just below the previous title.

  annoid_mid = gsn_add_annotation(bot_plot, txid_mid, amres)

  pres = True

  maximize_output(wks,pres)

frame (wks)

delete(plotvar)

end

Once again thank you,

Orestis Speyer,

Research Fellow, National Observatory of Athens
Institute for Environmental Research and Sustainable Development

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