NCL填色图（以contour为例）
2018-04-11 16:16阅读：
https://www.ncl.ucar.edu/Applications/color.shtml
res@cnFillOn
= True ;
首先打开填色（如果不设置cnFillColors或cnFillPalette使用默认填色）
；注意，以下①②③之间是独立的不同方法
；①①①①①①①①①①①①①①①---------------------------------------------
res@cnFillPalette
= 'precip_11lev' ；选择现成的调色板，名称在这里
；https://www.ncl.ucar.edu/Document/Graphics/color_table_gallery.shtml#Rainbow
；②②②②②②②②②②②②②②②----------------------------------------------
colors = (/'white','royal blue','light sky blue',\
'powder blue','light sea green',\
'pale
green','wheat','brown','pink'/) ；自定义color
array（不要和背景前景相同），名称见
；https:/
/www.ncl.ucar.edu/Document/Graphics/named_colors.shtml
res@cnFillPalette = colors
；③③③③③③③③③③③③③③③----------------------------------------------
res@cnFillColors =
(/-1,4,9,19,35,81,75,91,99/) ；从color
map中自行选择颜色组成colorbar，-1为透明，colormap数字代码见
；https://www.ncl.ucar.edu/Applications/colormap.shtml
；或
https://www.ncl.ucar.edu/Document/Graphics/ColorTables/ncl_default.shtml
；④④④④④④④④④④④④④④④----------------------------------------------
gsn_define_colormap(wks,'circular_0')
；该函数为wks定义一个colormap，colormap可用现成的调色板（如例①）或者自定义（如例②）
res@cnFillColors
= (/10,11,12,13,14,15,16,17,18,19/)
；从上句话定义的colormap中选取颜色（区别与例③中的colormap是默认的）
；==============================================
；画多个panel并统一给出colorbar
wks = gsn_open_wks('png', 'test_wuhan_rain2')
plot = new(2,graphic)
res
=
True
res@cnFillOn
= True
res@gsnDraw
= False
; Do not draw plot
res@gsnFrame
= False
; Do not advance frame
res@lbLabelBarOn
= False
; turn off the label bar
res@lbOrientation = 'Vertical' ；设置colorbal方向
plot(0) = gsn_csm_contour_map_ce(wks, p(0,:,:), res)
plot(1) = gsn_csm_contour_map_ce(wks, p(3,:,:), res)
resPanel
= True
; panel mods desired
resPanel@gsnPanelLabelBar= True
; label bar on panel
gsn_panel(wks,plot,(/2,1/),resPanel)
；==============================================
； 画colormap并翻转colormap，用于debug
wks = gsn_open_wks('x11','color')
gsn_define_colormap(wks,'gui_default')
;选一个colormap，如果没有这个步骤下一步会画默认colormap
gsn_draw_colormap(wks)
;
画colormap；V6.3支持新函数draw_color_palette(wks,'MPL_Paired',False)
gsn_reverse_colormap(wks)
; 将当前wks的colormap进行翻转
gsn_draw_colormap(wks)
;
画colormap
；==============================================
；同一个wks中用2个以上的colormap：对不同的graphic重新设置cnFillPalette/cnFillColors即可；如果是流线图和矢量图则设置stLevelPalette或者vcLevelPalette
wks = gsn_open_wks('png', 'test_wuhan_rain2')
plot = new(2,graphic)
res
= True
res@gsnDraw
= False ; do not draw picture
res@gsnFrame
= False ; do not advance
frame
res@cnFillOn
= True ;
turn on color fill
res@cnFillPalette
=
'precip_11lev'
plot(0) = gsn_csm_contour_map_ce(wks, p(0,:,:), res)
res@cnFillPalette =
'wgne15'
plot(1) = gsn_csm_contour_map_ce(wks, p(3,:,:), res)
resPanel
= True
; panel mods desired
gsn_panel(wks,plot,(/2,1/),resPanel)
；==============================================
；读取自定义的RGB文件作为colormap
wks = gsn_open_wks('x11','color')
cmap = RGBtoCmap('test_rgb.txt')
;
RCGtoCmap将文本文件的RGB转化为NCL colormap
gsn_define_colormap(wks,cmap)
gsn_draw_colormap(wks)
《test_rgb.txt》
220 220 220
95 158 160
221 160 221
205 200 177
238 233 191
78 238 148
238 99 99
139 10 80
139 126 102
139 69 19
；==============================================
；采用自定义rgb数组作为colormap
wks = gsn_open_wks('png','color')
; open a workstation and send data to
PNG
colors = (/ (/255,255,255/), (/244,255,244/), \
(/217,255,217/), (/163,255,163/), (/106,255,106/), \
(/43,255,106/), (/0,224,0/), (/0,134,0/),(/255,255,0/),\
(/255,127,0/) /) / 255. ;
确保是浮点型
res
= True
res@cnFillOn
= True
res@cnFillPalette = colors
plot = gsn_csm_contour_map(wks,prc(0,:,:), res)
