如何使用 IDL 对象图形在同一视图中绘制具有不同数据范围的两个图形

使用IDL对象图形时，若要在同一图形窗口中绘制具有不同数据范围的图形，需要对第二个图形的范围进行归一化处理以匹配第一个图形的范围。否则，两个图形将无法适配到同一视图中。

以下是一个基于两个随机数据集的归一化示例，这两个数据集在Y轴上具有不同的范围。

代码示例：

PRO test_IDLgrPlot


;create 2 random datasets

d1 = SMOOTH(RANDOMU(Seed1, 100)*(-200),10)

d2 = SMOOTH(RANDOMU(Seed, 100)*0.1,5)


;create window hierarchy

mywindow = IDLgrWindow()

myview = IDLgrView()

mymodel = IDLgrModel()


; create plot objects

plot1= IDLgrPlot(INDGEN(100),d1,COLOR=[0,0,255])

plot2= IDLgrPlot(INDGEN(100),d2,COLOR=[0,255,0])


; add plot objects and model to the view

myview.Add, mymodel

mymodel.Add, plot1

mymodel.Add, plot2


; normalized plot1 extension (blue line) to fit the view

plot1.GetProperty, XRANGE = xr, YRANGE = yr

xs = NORM_COORD(xr)

xs[0] = xs[0] - 0.5

ys = NORM_COORD(yr)

ys[0] = ys[0] - 0.5

plot1.SetProperty, XCOORD_CONV = xs, YCOORD_CONV = ys


; normalized plot2 extension (green line) to fit the view and to fit the same extension as plot1

plot2.GetProperty, XRANGE = xr2, YRANGE = yr2

xs2 = NORM_COORD(xr2)

xs2[0] = xs2[0] - 0.5

ys2 = NORM_COORD(yr2)

ys2[0] = ys2[0] - 0.5

plot2.SetProperty, XCOORD_CONV = xs2, YCOORD_CONV = ys2


; create axis

oTextXAxis = IDLgrText('X axis')

oTextYAxis = IDLgrText('Blue line')

oTextYAxis2 = IDLgrText('Green line')


oPlotYAxis = IDLgrAxis( 1, /EXACT, RANGE = yr, $

    XCOORD_CONV = xs, YCOORD_CONV = ys,TITLE = oTextYAxis, $

    LOCATION = [xr[0], yr[0]], TICKDIR = 0, $

    TICKLEN = (0.02*(xr[1] - xr[0])))


oPlotXAxis = IDLgrAxis( 0, /EXACT, RANGE = xr, $

    XCOORD_CONV = xs, YCOORD_CONV = ys,TITLE = oTextXAxis, $

    LOCATION = [xr[0], yr[0]], TICKDIR = 0, $

    TICKLEN = (0.02*(yr[1] - yr[0])))


oPlotYAxis2 = IDLgrAxis( 1, /EXACT, RANGE = yr2, $

    XCOORD_CONV = xs, YCOORD_CONV = ys2, TITLE = oTextYAxis2,$

    LOCATION = [xr[1], yr[0]], TICKDIR = 0, TEXTPOS=1, $

    TICKLEN = (0.02*(xr[1] - xr[0])))


oPlotXAxis2 = IDLgrAxis( 0, /EXACT, RANGE = xr, $

    XCOORD_CONV = xs, YCOORD_CONV = ys, $

    LOCATION = [xr[0], yr[1]],/NOTEXT,MAJOR=0,MINOR=0)   


;add axis to the model 

mymodel.Add, oPlotXAxis

mymodel.Add, oPlotYAxis

mymodel.Add, oPlotYAxis2

mymodel.Add, oPlotXAxis2


;draw the view

mywindow.Draw, myview


END

生成的图形将类似于下图所示：