Horizontal barplot for comparison two data - based on ratio - r

Question

I would like to create a horizontal barplot to compare two of my tables. I already did the comparison and created a table with ratio.
That's how the data looks like:
> dput(data)
structure(list(Name=c('Mazda RX4','Mazda RX4 Wag','Datsun 710','Hornet 4 Drive',
'Hornet Sportabout','Valiant','Duster 360','Merc 240D','Merc 230','Merc 280','Merc 280C',
'Merc 450SE','Merc 450SL','Merc 450SLC','Cadillac Fleetwood','Lincoln Continental',
'Chrysler Imperial','Fiat 128','Honda Civic','Toyota Corolla'),ratio=c(1.393319198903125,
0.374762569687951,0.258112791829808,0.250298480396529,1.272180366473129,0.318000456484454,
0.264074483447591,0.350798965144559,2.310541690719624,1.314300844213157,1.18061486696761,
0.281581177092538,0.270164442687919,2.335578882236703,2.362339701969396,1.307731925943769,
0.347550384302281,0.232276047899868,0.125643566969327,0.281209747680576),Freq=c(2L,9L,2L,2L,
4L,2L,2L,3L,3L,5L,2L,2L,2L,7L,2L,4L,4L,2L,2L,4L)),.Names=c('Name','ratio','Freq'),class=
'data.frame',row.names=c(NA,20L))
I would like to achieve something like that:
In the middle I would put 1. Based on the calculated ratio I would like to put the proper scale which goes up to 3 to the right for example and to 0 to the left (can be different of course).
Each of the cars should have a separate bar. It will give 20 bars on this plot.
Additional thing would be to put the numbers from column Freq on the plots. It's not obligatory but would help.

Answer 1

I don't really see how that plot makes much sense with your data, as there is no quantity that adds up to 1 (or a common total). It could make sense with proportions, not so much with ratio's. I might be missing something... Perhaps you're looking for something like this?
library(ggplot2)
r <- range(d$ratio)
br <- seq(floor(r[1]), ceiling(r[2]), 0.5)
ggplot(d, aes(x = Name, y = ratio - 1)) +
geom_bar(stat = 'identity', position = 'identity') +
coord_flip() +
ylab('ratio') + xlab('car') +
scale_y_continuous(breaks = br - 1, labels = br) +
theme_bw()
Add geom_text(aes(label = Freq), y = r[2] - 0.95) for the labels on the right side.
Or if you want to center the value of 1 (a bit more tricky):
r <- range(d$ratio)
m <- ceiling(max(abs(range(d$ratio))))
br <- seq(-m + 1, m - 1, 0.25)
ggplot(d, aes(x = Name, y = ratio - 1)) +
geom_bar(stat = 'identity', position = 'identity') +
geom_text(aes(label = Freq), y = m - 1.1) +
coord_flip() +
ylab('ratio') + xlab('car') +
scale_y_continuous(breaks = br, labels = br + 1, limits = c(-m + 1, m - 1),
expand = c(0, 0)) +
theme_bw()

Answer 2

## plot precomputations
yexpand <- 0.2;
barheight <- 0.8;
xlim <- c(0,3);
xticks <- seq(xlim[1L],xlim[2L],0.25);
ylim <- c(1-barheight/2-yexpand,nrow(data)+barheight/2+yexpand);
yticks <- seq_len(nrow(data));
cols <- c('#6F7EB3','#D05B5B');
## draw plot
par(mar=c(5,4,4,2)+0.1+c(0,3,0,0));
plot(NA,xlim=xlim,ylim=ylim,xaxs='i',yaxs='i',axes=F,ann=F);
segments(xlim[1L],ylim[1L],xlim[1L],ylim[2L],xpd=NA);
axis(1L,xticks,cex.axis=0.7);
axis(2L,yticks,data$Name,las=2L,cex.axis=0.7);
mtext(expression(italic(Ratio)),1L,3);
mtext(expression(italic(Car)),2L,5.5);
mtext(data$Freq,4L,0.75,at=yticks,las=2L,cex=0.7);
y1 <- seq_len(nrow(data))-barheight/2;
y2 <- seq_len(nrow(data))+barheight/2;
rect(xlim[1L],y1,data$ratio,y2,col=cols[1L],lwd=0.5);
rect(data$ratio,y1,xlim[2L],y2,col=cols[2L],lwd=0.5);
abline(v=1);