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我想在 R 中创建一个图，如下所示： 在此处输入图像描述

它是一种所谓的三轴比图，用于显示植物养分含量的比例。它需要从 0.01 到 100 的对数刻度，轴在 1 处交叉。我在此页面上找到了两个脚本，但是，它们有另一个目的，并不真正适合我的需要。这是一个：

get.coords <- function(a, d, x0, y0) {
a <- ifelse(a <= 90,90 - a, 450 - a)
data.frame(x = x0 + d * cos(a / 180 * pi),
y = y0+ d * sin(a / 180 * pi))
}

rotatedAxis <- function(x0, y0, a, d, symmetrical=FALSE, tickdist,  
ticklen,...) {
if(isTRUE(symmetrical)) {
axends <- get.coords(c(a, a + 180), d, x0, y0)
tick.d <- c(seq(0, d, tickdist), seq(-tickdist, -d, -tickdist))
} else {
axends <- rbind(get.coords(a, d, x0, y0), c(x0, y0))
tick.d <- seq(0, d, tickdist)
}
invisible(lapply(apply(get.coords(a, d=tick.d, x0, y0), 1, function(x) {
get.coords(a + 90, c(-ticklen, ticklen), x[1], x[2])
}), function(x) lines(x$x, x$y, ...)))
lines(axends$x, axends$y, ...)
}

plot.new()
plot.window(xlim=c(-70, 70), ylim=c(-70, 70), asp=1)
# Plot the rotated axes -original
rotatedAxis(0, 0, a=60, d=60,symmetrical=TRUE, tickdist=10, ticklen=1)
rotatedAxis(0, 0, a=120, d=60, symmetrical=TRUE, tickdist=10, ticklen=1)
rotatedAxis(0, 0, a=180, d=60, symmetrical=TRUE, tickdist=10, ticklen=1)

# Add text labels to circumference -original
text.coords <- get.coords(seq(0, 300, 60), 65, 0, 0)
text(text.coords$x, text.coords$y, c('I', 'A', 'S', 'E', 'C', 'R'))

points(0, 0, pch=21, bg=1, col=0, lwd=2, cex=2)

此代码创建旋转轴，但不能通过 xy 坐标而不是 xyz 来创建对数刻度和绘图点。

如果有人可以帮助我，那就太好了，原始论文没有提供该方法的描述，而且我在互联网上没有找到任何有用的东西。非常感谢！

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1 回答 1

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这段代码应该给你一个接近你想要的情节。我将它与一些示例数据一起使用来创建下面给出的图。代码使用基本图形，所以应该很容易修改。这些函数创建一个对数轴从 0.01 到 100 的图。

因为绘制的值是比率，所以它们中只有两个是独立的。第三个比率可以从其他两个计算出来，因此只需要指定两个比率。

我也没有找到太多关于情节的基础计算。此代码假定通过跟踪垂直于轴的点来读取每个点的比率。例如，Ca/Mg 上 10 处的点不会是每个大约 0.3，而不是 1。

在此处输入图像描述

makeAxes <- function(a3, # angles of axes, assumed at 120-degree separation, value indicates positive side from 3-o'clock
                     d, # length of half-axis in log10-units, 2 => 0.01-100
                     axLab, # labels for axes
                     cen=c(0,0), # center of axis
                     ticks=T, # should tick marks be included
                     tickLocs=c((1:9)*10^-2,(1:9)*10^-1,(1:9),(1:9)*10^1,100), # location of tick marks
                     tickLen=0.05, # dimension of tick marks
                     endText=T # are the values at the end of axes plotted
){

  # making an empty plot
  plot(NA,NA
       ,ylim=c(-d,d)*1.5 + cen[1]
       ,xlim=c(-d,d)*1.5 + cen[2]
       ,bty='n'
       ,axes = F
       ,ylab=''
       ,xlab='')

  # adding axis lines and notations
  for(i in 1:3){

    # coordinates of x and y ends of axes
    # col1 = x values
    matTemp <- matrix(0,2,2)

    matTemp[,1] <- c(cen[1] + d*cos(a3[i]*pi/180),cen[1] - d*cos(a3[i]*pi/180))
    matTemp[,2] <- c(cen[2] + d*sin(a3[i]*pi/180),cen[2] - d*sin(a3[i]*pi/180))

    # plotting lines
    lines(matTemp[,1],matTemp[,2])

    # adding text for axes
    text(x=matTemp[1,1]*1.4,y=matTemp[1,2]*1.4,
         labels=axLab[i])

    if(endText){
      text(x=matTemp[,1]*1.1,
           y=matTemp[,2]*1.1,
           labels=c(10^d,10^-d),
           cex=0.8
          )
      text(cen[1],cen[2],
           lab=1,
           pos=4,
           cex=0.8
           )
    }

    # adding tick marks
    if(ticks){

      # values are the point on the axis plus a correction to make it perpendicular
      xVals1 <- cen[1] + log10(tickLocs)*cos(a3[i]*pi/180) - tickLen*sin(a3[i]*pi/180)
      yVals1 <- cen[2] + log10(tickLocs)*sin(a3[i]*pi/180) - tickLen*cos(a3[i]*pi/180)

      xVals2 <- cen[1] + log10(tickLocs)*cos(a3[i]*pi/180) + tickLen*sin(a3[i]*pi/180)
      yVals2 <- cen[2] + log10(tickLocs)*sin(a3[i]*pi/180) + tickLen*cos(a3[i]*pi/180)

      # plotting lines as tick marks
      for(j in 1:length(xVals1)){
        lines(c(xVals1[j],xVals2[j]),c(yVals2[j],yVals1[j]))
      }
    }
  }
}

addPoints <- function(df, # data frame of values, must have axis columns
                     cen=c(0,0), # center of axis
                     a3 # angles of axes, assumed at 120-degree separation, value indicates positive side from 3-o'clock
){

  # temporary data frame for calculations
  dftemp <- df

  # calculation of log values
  dftemp$axis1log <- log10(dftemp$axis1)
  dftemp$axis2log <- log10(dftemp$axis2)
  dftemp$axis3log <- log10(dftemp$axis3)

  # calculation of values along axis 1
  dftemp$axis1log_xvals <- cen[1] + dftemp$axis1log*cos(a3[1]*pi/180)
  dftemp$axis1log_yvals <- cen[2] + dftemp$axis1log*sin(a3[1]*pi/180)

  # calculation of values along axis 2
  dftemp$axis2log_xvals <- cen[1] + dftemp$axis2log*cos(a3[2]*pi/180)
  dftemp$axis2log_yvals <- cen[2] + dftemp$axis2log*sin(a3[2]*pi/180)

  # slope calcuation
  dftemp$axis1_perp <- sin((a3[1]+90)*pi/180)/cos((a3[1]+90)*pi/180)
  dftemp$axis2_perp <- sin((a3[2]+90)*pi/180)/cos((a3[2]+90)*pi/180)

  # intersection points
  # y1 = ax1 + c
  # y2 = bx2 + d
  a <- dftemp$axis1_perp
  b <- dftemp$axis2_perp

  c <- dftemp$axis1log_yvals - dftemp$axis1_perp*dftemp$axis1log_xvals
  d <- dftemp$axis2log_yvals - dftemp$axis2_perp*dftemp$axis2log_xvals

  dftemp$intersectx <- (d-c)/(a-b)
  dftemp$intersecty <- a*(d-c)/(a-b)+c

  points(dftemp$intersectx
         ,dftemp$intersecty
         ,pch=19 # plotting symbol
         ,col='gray48' # colors of points
         ,cex=1.2 # multiplier for plotting symbols
         ) 
}

# example data
labs <- c("a","b","c","d","e","f","g")
k <- c(150,  100, 3000, 3500, 10,  10,  30)
ca <- c(500, 120, 350,  100,  10,  10,  30)
mg <- c(50,  450, 220,  350,  10,  100, 60)

# conversion into data frame
dataPlot <- as.data.frame(list('labs'=labs,'k'=k,'ca'=ca,'mg'=mg)

# calcuations with data frame
dataPlot$axis1 <- dataPlot$ca/dataPlot$mg
dataPlot$axis2 <- dataPlot$k/dataPlot$ca
dataPlot$axis3 <- dataPlot$mg/dataPlot$k

# making axes
makeAxes(a3=c(90,-30,210),
         d=2,
         axLab=c("Ca/Mg", "K/Ca",  "Mg/K" ))

# adding points
addPoints(df=dataPlot,
          a3=c(90,-30,210))
于 2017-08-24T12:51:58.287 回答