How do we plot chessboard (N by N) grid?

Question

If I have a CSV as such:

row,column
1,0
5,1
7,2
2,3
0,4
3,5
6,6
4,7

Populated black square from CSV data results in:

Mine draws black squares on the underlying plot. Having trouble getting the black squares in the right part. I am still new to R so I am having some difficulty. Where am I going wrong?

library(data.table)

library(reshape2)
library(ggplot2)

data_csv <- fread('./data.csv')

mx <- matrix(data_csv, nrow=8, ncol=8)

ggplot(melt(mx), aes(x=Var1, y=Var2)) + geom_tile()

Trying to make it dynamic so that if the CSV grows to n lines, it will still handle.

Answer 1

First read in the data:

chessdat <- read.table(text='row,column
1,0
5,1
7,2
2,3
0,4
3,5
6,6
4,7', sep =',', header = T)

Because geom_tile is centered at the point, let's give an offset

offset <- 0.5
chessdat2 <- chessdat + offset

Then plot as you had done:

ggplot(chessdat2, aes(row,column)) + geom_tile() + theme_bw()

Which gives:

Then playing with the format a bit, we can get to the chessboard:

ggplot(chessdat2, aes(row,column)) + geom_tile() + 
     theme_bw() + 
     theme(panel.grid.major = element_line(size = 2, color='black'),       
     panel.grid.minor = element_line(size=2, color = 'black'),
     axis.ticks = element_blank(), 
     axis.text = element_blank(), 
     axis.title = element_blank()) + 
     coord_cartesian(xlim=c(0,8), ylim=c(0,8))

Which gives the plot: