Categorical bubble plot for mapping studies

问题:

How to create a categorical bubble plot, using GNU R, similar to that used in systematic mapping studies (see below)?

EDIT: ok, here's what I've tried so far. First, my dataset (Var1 goes to the x-axis, Var2 goes to the y-axis):

> grid                          Var1                      Var2 count 1              Does.Not.apply            Does.Not.apply    53 2               Not.specified            Does.Not.apply    15 3   Active.Learning..general.            Does.Not.apply     1 4      Problem.based.Learning            Does.Not.apply     2 5              Project.Method            Does.Not.apply     4 6         Case.based.Learning            Does.Not.apply    22 7               Peer.Learning            Does.Not.apply     6 10                      Other            Does.Not.apply     1 11             Does.Not.apply             Not.specified    15 12              Not.specified             Not.specified    15 21             Does.Not.apply Active.Learning..general.     1 23  Active.Learning..general. Active.Learning..general.     1 31             Does.Not.apply    Problem.based.Learning     2 34     Problem.based.Learning    Problem.based.Learning     2 41             Does.Not.apply            Project.Method     4 45             Project.Method            Project.Method     4 51             Does.Not.apply       Case.based.Learning    22 56        Case.based.Learning       Case.based.Learning    22 61             Does.Not.apply             Peer.Learning     6 67              Peer.Learning             Peer.Learning     6 91             Does.Not.apply                     Other     1 100                     Other                     Other     1 

Then, trying to plot the data:

# Based on http://flowingdata.com/2010/11/23/how-to-make-bubble-charts/ grid <- subset(grid, count > 0) radius <- sqrt( grid$count / pi ) symbols(grid$Var1, grid$Var2, radius, inches=0.30, xlab="Research type", ylab="Research area") text(grid$Var1, grid$Var2, grid$count, cex=0.5) 

Here's the result:

Problems: axis labels are wrong, the dashed grid lines are missing.

回答1:

Here is ggplot2 solution. First, added radius as new variable to your data frame.

grid$radius <- sqrt( grid$count / pi ) 

You should play around with size of the points and text labels inside the plot to perfect fit.

library(ggplot2) ggplot(grid,aes(Var1,Var2))+   geom_point(aes(size=radius*7.5),shape=21,fill="white")+   geom_text(aes(label=count),size=4)+   scale_size_identity()+   theme(panel.grid.major=element_line(linetype=2,color="black"),         axis.text.x=element_text(angle=90,hjust=1,vjust=0)) 

回答2:

Here a version using levelplot from latticeExtra.

library(latticeExtra) levelplot(count~Var1*Var2,data=dat,           panel=function(x,y,z,...)           {             panel.abline(h=x,v=y,lty=2)             cex <- scale(z)*3             panel.levelplot.points(x,y,z,...,cex=5)             panel.text(x,y,label=z,cex=0.8)           },scales=(x=list(abbreviate=TRUE))) ## to get short labels 

To get the size of bubble proprtional to the count , you can do this

library(latticeExtra) levelplot(count~Var1*Var2,data=dat,           panel=function(x,y,z,...)           {             panel.abline(h=x,v=y,lty=2)             cex <- scale(z)*3             panel.levelplot.points(x,y,z,...,cex=5)             panel.text(x,y,label=z,cex=0.8)            }) 

I don't display it since the render is not clear as in the fix size case.

回答3:

This will get you started by adding the tick marks to your xaxis.

To add the lines, just add a line at each level

ggs <- subset(gg, count > 0) radius <- sqrt( ggs$count / pi )  # ggs$Var1 <- as.character(ggs$Var1)  # set up your tick marks  #  (this can all be put into a single line in `axis`, but it's placed separate here to be more readable) #-------------- # at which values to place the x tick marks x_at <- seq_along(levels(gg$Var1)) # the string to place at each tick mark x_labels <-   levels(gg$Var1)   # use xaxt="n" to supress the standard axis ticks  symbols(ggs$Var1, ggs$Var2, radius, inches=0.30, xlab="Research type", ylab="Research area", xaxt="n") axis(side=1, at=x_at, labels=x_labels)  text(ggs$Var1, ggs$Var2, ggs$count, cex=0.5) 

---

also, notice that instead of calling the object grid I called it gg, and then ggs for the subset. grid is a function in R. While it is "allowed" to overwrite the function with an object, it is not recommended and can lead to annoying bugs down the line.

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