strange interaction of geom_raster and scale_{x,y}_continuous

[paciorek]

If one applies scale_{x,y}_continuous to a raster plot but sets the x- or y-axis limits to be smaller than the extent of the data grid, the resulting plotting of the raster cells is distorted, with the cells shrunk in the dimension where the limit is set "too" small.

## Setup simple grid.
dat = expand.grid(x = seq(-2, 2, by = 1), y = seq(-2, 2, by = 1))
dat$val <- (1:nrow(dat))/nrow(dat)

## Case A: This plots fine without scale_{x,y}_continuous.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0)

## Case B: This plots fine too with limits set to be larger than extent of data grid.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0) + scale_x_continuous(limits = c(-3.5, 3.5)) + scale_y_continuous(limits = c(-3.5,3.5))

## Case C: y limits  are now more restricted than data limits and don't align with the data grid.
## Scaling in y direction is now distorted.
## Note that the center of the middle grid box should be at (0,0) where the horizontal and vertical lines intersect.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0) + scale_x_continuous(limits = c(-2.5, 2.5)) + scale_y_continuous(limits = c(-2,2.5))

Here's info on my setup:

> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 18.04.2 LTS

[...snip ...]

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
[1] ggplot2_3.2.1    

[clauswilke]

Could you please run your example through the reprex package and repost here? https://reprex.tidyverse.org/articles/articles/magic-reprex.html

[paciorek]

Here it is.

library(ggplot2)

## Setup simple grid.
dat = expand.grid(x = seq(-2, 2, by = 1), y = seq(-2, 2, by = 1))
dat$val <- (1:nrow(dat))/nrow(dat)

## Case A: This plots fine without scale_{x,y}_continuous.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0)

## Case B: This plots fine too with limits set to be larger than extent of data grid.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0) + scale_x_continuous(limits = c(-3.5, 3.5)) + scale_y_continuous(limits = c(-3.5,3.5))

## Case C: y limits  are now more restricted than data limits and don't align with the data grid.
## Scaling in y direction is now distorted.
## Note that the center of the middle grid box should be at (0,0) where the horizontal and vertical lines intersect.
ggplot() + geom_raster(data = dat, aes(x = x, y = y, fill = val)) + geom_hline(yintercept = 0) + geom_vline(xintercept = 0) + scale_x_continuous(limits = c(-2.5, 2.5)) + scale_y_continuous(limits = c(-2,2.5))

^{Created on 2019-09-23 by the reprex package (v0.3.0)}

[thomasp85]

This was a bug - thanks for reporting. Just an FYI, you'd probably want to zoom using the xlim and ylim arguments to coord_cartesian() rather than using the scales. The latter will completely remove data that falls outside of the scale limits while the former will just zoom in as expected

[lock]

This old issue has been automatically locked. If you believe you have found a related problem, please file a new issue (with reprex) and link to this issue. https://reprex.tidyverse.org/