MAS2908 - syntax summary

For visualising multivariate / non-geospatial data

library(ggplot2)
library(dplyr) # when filter(), mutate(), count(), arrange() etc. needed
library(readr) # when read_csv() needed
library(readxl) # when read_xls() or read_xlsx() needed
library(lubridate) # when make_date() or make_datetime() needed

<data> <- read_csv("<file>.csv") # or read_xlsx("<file>.xls", sheet = "<sheet>", ...)

<data> |> # required
  
  filter(<condition>) |>
  mutate(<varname> = <expression>) |>  # optional data manipulation
  count(<varname>) |>
  arrange(<varname>) |>
  
  ggplot(aes(<aesthetic> = <varname>, <aesthetic> = <varname>, ...)) + # required
  
       histogram
       density
       boxplot
       bar
       point
       line
  geom_path(...) + # required
       jitter
       count
       smooth
       col
       qq
       qq_line

  geom_*(...) + # optional additional geoms

  labs(<aesthetic> = "<label>", <aesthetic> = "<label>", ...) + # required

               grey
               brewer
               fermenter
               distiller
        color  viridis_b
  scale_colour_viridis_c(...) + # recommended, non-exhaustive list here
        fill   viridis_d
               steps
               steps2
               gradient
               gradient2
               manual

  scale_<aesthetic>_<scalename>(...) + ... + # optional additional scales

          discrete
  scale_x_continuous(...) + # optional
        y log10
          date

  coord_cartesian(xlim = c(...), ylim = c(...)) + # recommended

  stat_summary(fun = ...) + # optional
  
  facet_grid(<varname> ~ <varname>) + # optional
        wrap(~ <varname>)

        grey
        bw
  theme_classic(base_size = ...) + # optional
        minimal
        void

  theme(legend.position = "...") # optional

Notes on the placeholders:

• <aesthetic> is the name of a ggplot2 aesthetic without quotes. Common aesthetics are: x, y, colour, fill, size, shape, linetype, alpha.
• <varname> is the name of a column in <data> without quotes.
• <label> (in labs()) is a human-readable string with quotes, e.g., "Engine Displacement (L)".

For visualising geospatial data

library(ggplot2)
library(dplyr) # for optional data manipulations
library(sf) # for read_sf() & other manipulations with geospatial data
library(rnaturalearth) # for background map data

<data> <-
  read_sf("<file>.shp") |> # required
  ... # optional data manipulation using dplyr functions
  
<map> <-
  ne_countries(scale = "medium", country = "<country name>", returnclass = "sf")

ggplot() +

  geom_sf(data = <map>) + # recommended

  geom_sf(aes(<aesthetic> = <varname>, ...), data = <data>) + # required

  labs(<aesthetic> = "<label>", ...) + # optional

               grey
               brewer
               fermenter
               distiller
        color  viridis_b
  scale_colour_viridis_c(...) + # recommended, non-exhaustive list here
        fill   viridis_d
               steps
               steps2
               gradient
               gradient2
               manual

  scale_<aesthetic>_<scalename>(...) + ... + # optional additional scales

  theme_void(base_size = ...) + # optional

  theme(legend.position = "...") # optional

Notes:

• Unlike multivariate / non-geospatial data, x and y are usually not needed as aesthetics in geom_sf(). If POINT is the geometry type in the data, colour and size are the likely aesthetics. If POLYGON or MULTIPOLYGON is the geometry type, fill is the likely aesthetic.
• If fill is used to map a variable, it might be useful to set colour to NA i.e.
  ... + geom_sf(aes(fill = <varname>, ...), data = <data>, colour = NA) + ...