X- and Y- axis tick marks

[David Simons]

Not sure if this is within the scope of this package but I've not had much luck trying to find other methods.

I am facetting several plots and then plotting them as a grid using cowplot::plot_grid(). This gets me what I want but there is an issue with the number of tick marks. I'd like to reduce the numbers of ticks on each sublot (to say 2) but not having much luck with scale_x_continuous(n.breaks = 2, breaks = waiver()) which I think should work. Using scales::breaks_pretty(n = 2)) throws up an error Error in min(lon) : invalid 'type' (closure) of argument which I think is because of the structure that is fed into the ggplot(data).

The code for each row is currently done in a for loop which is then fed to plot_grid()

for(i in 1:length(grids_with_traps))  {
  grids_plot[[i]] <- ggplot() + 
    geom_spatraster_rgb(data = bg[[i]]) +
    geom_sf(data = grids_with_traps[[i]] %>%
              mutate(landuse = str_to_title(landuse)),
            aes(fill = tn, colour = tn)) +
    coord_sf(expand = FALSE) +
    scale_colour_viridis_c(limits = c(0, 100)) +
    scale_fill_viridis_c(limits = c(0, 100)) +
    scale_x_continuous(breaks = scales::breaks_pretty(n = 2)) +
    guides(colour = "none") +
    facet_wrap(~ landuse) +
    labs(fill = "Number Trap-Nights",
         title = str_to_title(unique(grids_with_traps[[i]]$village))) +
    theme_bw() +
    theme(legend.position = "none")
}

A reproducible example may be easier using nc, neither of these do what I think they should.

ggplot() + 
  geom_sf(data = nc %>%
            filter(CNTY_ID %in% c(1825, 1827)),
          aes(fill = AREA, colour = AREA)) +
  coord_sf(expand = FALSE) +
  scale_colour_viridis_c(limits = c(0, 100)) +
  scale_fill_viridis_c(limits = c(0, 100)) +
  scale_x_continuous(breaks = scales::pretty_breaks(n = 2)) +
  guides(colour = "none") +
  facet_wrap(~ CNTY_ID) +
  labs(fill = "AREA") +
  theme_bw() +
  theme(legend.position = "none")`

ggplot() + 
  geom_sf(data = nc %>%
            filter(CNTY_ID %in% c(1825, 1827)),
          aes(fill = AREA, colour = AREA)) +
  coord_sf(expand = FALSE) +
  scale_colour_viridis_c(limits = c(0, 100)) +
  scale_fill_viridis_c(limits = c(0, 100)) + 
  scale_x_continuous(n.breaks = 2, breaks = waiver()) +
  guides(colour = "none") +
  facet_wrap(~ CNTY_ID) +
  labs(fill = "AREA") +
  theme_bw() +
  theme(legend.position = "none")

[Diego H.]

You can try #45 or https://dieghernan.github.io/tidyterra/articles/faqs.html#axis-breaks.

[David Simons]

Perfect, thanks.