I am plotting spatial map, using 'plot.sf' function in which key shows the values from breaks like legend. I want to change the size of these values and making bold. I am trying to make the key values bold but not working. Please help me changing the key values size and making them bold.
plot(merge_yield["water volume"], breaks = c(0.0,2000, 4000, 6000, 8000, 10000, 12000),
pal = colorRampPalette(c("orange", "green")),
main = "water volume in 2018",
key.pos = 4, axes = TRUE, key.width = lcm(1.3), key.length = 1.0,
cex.main = 1.50)