How to customize legend in ggplot for multiple layers in a map?

Question

I'm trying to fix my caption but I'm having trouble creating it. I wanted a caption for the classes (fill), the shape limit (color), the points (color) and the grid (fill=NA). I put them all in aes () but I don't have the expected result. Can anybody help me? Thanks!

library(geobr)
library(sf)
library(ggplot2)
library(ggspatial)

#Directory

getwd()

#Download spatial data ------------------------------------------------

download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.dbf", 
              destfile = "SP_3543907_USO.dbf", mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.prj", 
              destfile = "SP_3543907_USO.prj", mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.shp", 
              destfile = "SP_3543907_USO.shp", mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.shx", 
              destfile = "SP_3543907_USO.shx", mode = "wb")

#Import spatial data --------------------------------------------------

uso <- sf::st_read("SP_3543907_USO.shp")
uso
plot(uso$geometry)

#Area limit

rio_claro_limit <- geobr::read_municipality(code_muni = 3543907, year = 2015)
rio_claro_limit
plot(rio_claro_limit$geom)

#Random sample points

set.seed(123)
pts <- st_sample(uso, size = 20, type="random") %>% st_sf

#Grid 50km x 50km

grid_50 <- st_make_grid(uso, cellsize = c(5000, 5000)) %>% 
  st_sf(grid_id = 1:length(.))

#Labels grid

grid_lab <- st_centroid(grid_50) %>% cbind(st_coordinates(.))

#Points in grid

pts %>% st_join(grid_50, join = st_intersects) %>% as.data.frame


#Map --------------------------------------------------------------------

ggplot() +
  geom_sf(data = uso, aes(fill = CLASSE_USO, color = NA)) +
  geom_sf(data = rio_claro_limit, aes(color = 'black', fill = NA)) +
  geom_sf(data = pts, aes(color = 'red'), size = 1.7) + 
  geom_sf(data = grid_50, aes(fill=NA), lwd = 0.3) +
  geom_text(data = grid_lab, aes(x = X, y = Y, label = grid_id), size = 2) +
  xlab("")+
  ylab("")+
  scale_fill_manual(name="Classes de Uso", values = c("blue", "orange", "gray30", "forestgreen", "green", NA))+
  scale_color_identity(guide = "legend")

Can you rephrase your question? I read it multiple times, but it is not clear to me what you would like to do. — user
– user, Commented Oct 7, 2020 at 16:47
Of course! I would like to create a legend for the shape limit and for the grids, but I found that it is only possible to create two categories for the legend: color and fill. If you know, I would still like to remove the border to the point legend. — Igor Cobelo
– Igor Cobelo, Commented Oct 8, 2020 at 14:05
You could also add the shape of the markers, despite color and fill. Only place color and fill inside the aes when you want it to show up in the legend for the that particular geometry. The borders might be related to that aes specification. The grey background of the legend items can be removed by mentioning legend.key = element_blank() in the theme. — user
– user, Commented Oct 8, 2020 at 18:44

stefan · Accepted Answer · 2020-10-15 17:38:44Z

3

Your desired result could be achieved like so:

I moved all fill=NA and color=NA out of the aes() statements. As usual if you want to fix a color, fill or more generally any aes on a specific value then it's best to put it outside of aes() except for the case that you want it to appear in the legend.
Set the so called key_glyph, i.e. the icon drawn in the legend, of the "point" layers to "point".

As these steps also removed the black border around the fill keys I added a guides layer to get that back. Personally I would remove the black border, but hey, it's your plot. (:

library(geobr)
library(sf)
library(ggplot2)
library(ggspatial)

ggplot() +
  geom_sf(data = uso, aes(fill = CLASSE_USO), color = NA) +
  geom_sf(data = rio_claro_limit, aes(color = 'black'), fill = NA, key_glyph = "point") +
  geom_sf(data = pts, aes(color = 'red'), size = 1.7, key_glyph = "point") + 
  geom_sf(data = grid_50, fill = NA, lwd = 0.3) +
  geom_text(data = grid_lab, aes(x = X, y = Y, label = grid_id), size = 2) +
  xlab("")+
  ylab("")+
  scale_fill_manual(name="Classes de Uso", values = c("blue", "orange", "gray30", "forestgreen", "green", NA)) +
  guides(fill = guide_legend(override.aes = list(color = "black"))) +
  scale_color_identity(guide = "legend")

answered Oct 15, 2020 at 17:38

stefan

130k6 gold badges42 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

yuliaUU Over a year ago

how to edit the legend part named color? i would like to replace the name of that thing to something else and also put names instead of "red" and "black".

stefan Over a year ago

Hi @yuliaUU. To could change the title via scale_color_identity(name = ...) and the labels could be set inside the geom_sf(aes(color = "...")).

yuliaUU Over a year ago

Thanks a lot! I was doing it with scale_color_manual and that is why could not get it to work

Collectives™ on Stack Overflow

How to customize legend in ggplot for multiple layers in a map?

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related