<div dir="ltr"><div>It looks like NCL example topo_4 does what you want. Try carefully changing this example for your region of interest.</div><div><br></div><div>Those thin lines are the "fill value perimeter line" at the -100 meter elevation. You can experiment with resources that control or modify this feature. Look at the cnMissingValPerim* resources. Try res@cnMissingValPerimOn = False. Also look at your color map and color fill settings. You might try setting the ocean fill colors to white or light blue, instead of transparent.</div><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Oct 15, 2023 at 4:21 AM lzl lai via ncl-talk <<a href="mailto:ncl-talk@mailman.ucar.edu">ncl-talk@mailman.ucar.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi <div><br><div>I have a problem for deleting those thin lines (the red arrow pointed area)</div><div>. Could you please help me to remove it? Thanks a lot!</div><div><br></div><div>I use "ETOPO_2022_v1_60s_N90W180_bed.nc" ,for drawing topography,</div><div> and "gadm41_TWN_0.shp" , for drawing coastline in Taiwan</div><div><br></div><div>my scrip is below :<br></div><div>========================================</div><div>;---Read data<br>; topo_file = "../topo/ETOPO_2022_v1_60s_N90W180_geoid.nc"<br> topo_file = "../topo/ETOPO_2022_v1_60s_N90W180_bed.nc"<br> f = addfile(topo_file,"r")<br> elev = f->z<br>;<br>; Set all values below -100 to missing, hence removing all<br>; the ocean elevation values. The ocean will be filled in<br>; a light blue (see mpOceanFillColor below).<br>;<br> elev = where(elev.lt.-100.,elev@_FillValue,elev)<br><br></div><div>;;file --- 2<br> shpdir = "/home/lzl/data2/lzl/CWBtrend/topo/TW/"<br> filename ="gadm41_TWN_0.shp"<br></div><div><br></div><div> wks = gsn_open_wks("pdf","./pic/TW_topo") ; send graphics to PNG file<br> gsn_define_colormap(wks,"WhiteBlueGreenYellowRed")<br></div><div><br> res = True<br> res@gsnMaximize = True ; maximize plot in frame<br><br> res@cnFillOn = True ; turn on contour fill<br>; res@cnFillPalette = cmap(2:,:) ; set color map<br> res@cnLinesOn = False ; turn off contour lines<br> res@cnLineLabelsOn = False ; turn off line labels<br> res@cnInfoLabelOn = False ; turn off info label<br> res@lbBoxLinesOn = False ; turn off labelbar box lines<br><br> res@cnFillMode = "MeshFill" ; for faster draw<br><br>;---Pick "nice" contour levels<br>; mnmxint = nice_mnmxintvl( min(elev), max(elev), 18, False)<br> mnmxint = nice_mnmxintvl( min(elev), max(elev), 5, False)<br><br> printVarSummary(mnmxint)<br> print(mnmxint(1))<br> print(mnmxint(2))<br> res@cnLevelSelectionMode = "ManualLevels"<br> res@cnMinLevelValF = 100.<br> res@cnMaxLevelValF = mnmxint(1)<br> res@cnLevelSpacingF = mnmxint(2)/20. ; Increase the number of levels<br> ; by choosing a smaller spacing.<br> ;higher number mean higher resol<br></div><div><br></div><div> res@gsnAddCyclic = False ; don't add longitude cyclic point<br><br>;---Zoom in on map<br> res@mpLimitMode = "LatLon"<br> res@mpMinLatF = 21.5<br> res@mpMaxLatF = 25.5<br> res@mpMinLonF = 119.5<br> res@mpMaxLonF = 122.5<br>; res@mpCenterLonF = (res@mpMinLonF + res@mpMaxLonF) / 2.<br><br> res@mpFillOn = True<br></div><div><br></div><div> res@mpInlandWaterFillColor="Background"<br> res@mpOceanFillColor = "transparent"<br> res@mpLandFillColor = "transparent"<br><br> res@mpFillDrawOrder = "PostDraw"<br></div><div> res@mpDataBaseVersion = "MediumRes"<br> res@mpOutlineOn = False<br> res@pmTickMarkDisplayMode = "Always"<br> res@mpGeophysicalLineThicknessF = 2<br> plot = gsn_csm_contour_map(wks,elev,res)<br><br></div><div> nres = True<br> lnres@gsLineColor = "black"<br> lnres@gsLineThicknessF = 3.0<br> dum = gsn_add_shapefile_polylines(wks,plot,shpdir+filename,lnres)<br></div><div><br></div><div> draw(plot) ; This will draw the map and the shapefile outlines.<br> frame(wks)<br></div></div></div>
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