ggplot: is it possible to overlap 2 plots?

Question

I'm drawing two maps of my country using shapefiles: one for regions with real wage lower than 700 and the other one for the regions with real wage greater than 700. This is my code

plot 1 <-right_join(prov2022, dataset, by = "COD_PROV") %>% 
         ggplot(aes(fill = `Real Wage` < 700))+
         geom_sf() +
         theme_void() +
         theme(legend.position = "none", legend.title=element_blank())+
         scale_fill_manual(values = c('white', 'orange'))
  

plot 2<- right_join(prov2022, dataset, by = "COD_PROV") %>% 
         ggplot(aes(fill = `Real Wage` > 700))+
         geom_sf() +
         theme_void() +
         theme(legend.position = "none", legend.title=element_blank())+
         scale_fill_manual(values = c('white', 'red'))

It works perfectly.

Is there a way to overlap the second plot on the first one?? More precisely, I need to put the filled regions of the second plot into the first one

It's easier to help you if you include a simple [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) with sample input and desired output that can be used to test and verify possible solutions. Since we can't run the code because we don't have the data, it's unclear what the plots currently look like and what you want them to look like. Normally you would just call `ggplot` once if you want one plot output or use a package like `patchwork` to combine multiple ggplot objects — MrFlick, Feb 21 '23 at 17:00
@MrFlick you're right! I've update the question with the output plots that I want overlap. I need to have a unique map with both orange anD red regions. I have no idea instead how to add the shapesfiles, because it is an entire directory full of files — io_boh, Feb 21 '23 at 17:12

stefan · Accepted Answer · 2023-02-21T17:51:31.007

You could create one map and use e.g. dplyr::case_when to create intervals to be mapped on fill or use cut.

Using the default example from ggplot2::geom_sf:

library(ggplot2)
library(sf)
#> Linking to GEOS 3.10.2, GDAL 3.4.2, PROJ 8.2.1; sf_use_s2() is TRUE

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf(aes(fill = dplyr::case_when(
    AREA < .1 ~ "a",
    AREA > .15 ~ "c",
    .default = "b"
  ))) +
  scale_fill_manual(
    values = c("red", "white", "orange"),
    labels = c(a = "< .1", b = ".1 <= x <= .15", c = "> .15")
  ) +
  labs(fill = NULL)

EDIT To add more colors or categories add more conditions to case_when. However, if you have a lot of conditions then using cut might be the easier approach.

Note: In case you wondered about why I use the letters. This was a quick and easy approach to order the categories.

library(ggplot2)
library(sf)
#> Linking to GEOS 3.10.2, GDAL 3.4.2, PROJ 8.2.1; sf_use_s2() is TRUE

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf(aes(fill = dplyr::case_when(
    AREA < .05 ~ "a",
    AREA >= .05 & AREA < .1 ~ "b",
    AREA > .15 & AREA < .2 ~ "c",
    .default = "d"
  ))) +
  scale_fill_manual(
    values = c("red", "orange", "brown", "white"),
    labels = c(a = "< .05", b = ".05 <= x < .1", c = "> .15" , d = ".1 <= x <= .15 OR x > .2")
  ) +
  labs(fill = NULL)

hi @stefan and thank you very much for the answer! It is perfect for my purposes. How can I add a fourth and fifth colors into your code? for example brown for the values between .15 and .20 and still white for the ones >.20 — io_boh, Feb 21 '23 at 17:37
See my edit on how to generalize the approach for more categories. — stefan, Feb 21 '23 at 17:53

ggplot: is it possible to overlap 2 plots?

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