为图制作2D图例-双变量Choropleth贴图 [英] Make a 2D legend for a plot - bi-variate choropleth maps

问题描述

我一直在使用二元变色函数图，并且一直陷于如何创建类似于

I have been playing with bi-variate choropleth maps and have gotten stuck on how to create a 2d legend similar to the one by Joshua Stevens shown here:

为说明这一挑战，我们不需要使用地图.下面的代码就足够了:

To illustrate the challenge we don't need to use a map. The code below will suffice:

#test desired legend appearance
library(ggplot2)
library(reshape2)
#use color scheme shown here http://www.joshuastevens.net/cartography/make-a-bivariate-choropleth-map/
bvColors=c("#be64ac","#8c62aa","#3b4994","#dfb0d6","#a5add3","#5698b9","#e8e8e8","#ace4e4","#5ac8c8")
legendGoal=melt(matrix(1:9,nrow=3))
test<-ggplot(legendGoal, aes(Var1,Var2))+ geom_tile(aes(fill = as.factor(value)))
test<- test + scale_fill_manual(name="Var1 vs Var2",values=bvColors,drop=FALSE)
test

它将创建一个类似于我要使用的图例的图，但是图例当然是所有级别的垂直条.我希望图例看起来像情节本身.有没有办法做到这一点?谢谢！

It creates a plot that looks like the legend I am going for but of course the legend is a vertical bar of all the levels. I want the legend to look like the plot itself. Is there a way to do that? Thanks!

推荐答案

不是一个完整的答案，但我认为您需要使用

Not a complete answer, but I think you need to play with guides.

ggplot(legendGoal, 
       aes(Var1,Var2,
           col=as.factor(value),
           fill=as.factor(value))) +
  geom_tile() +
  guides(col = guide_legend(nrow = 3))

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