This set of geom, stat, and coord are used to visualise simple feature (sf)
objects. For simple plots, you will only need geom_sf()
as it
uses stat_sf()
and adds coord_sf()
for you. geom_sf()
is
an unusual geom because it will draw different geometric objects depending
on what simple features are present in the data: you can get points, lines,
or polygons.
For text and labels, you can use geom_sf_text()
and geom_sf_label()
.
coord_sf(xlim = NULL, ylim = NULL, expand = TRUE, crs = NULL, datum = sf::st_crs(4326), label_graticule = waiver(), label_axes = waiver(), ndiscr = 100, default = FALSE, clip = "on") geom_sf(mapping = aes(), data = NULL, stat = "sf", position = "identity", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...) geom_sf_label(mapping = aes(), data = NULL, stat = "sf_coordinates", position = "identity", ..., parse = FALSE, nudge_x = 0, nudge_y = 0, label.padding = unit(0.25, "lines"), label.r = unit(0.15, "lines"), label.size = 0.25, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, fun.geometry = NULL) geom_sf_text(mapping = aes(), data = NULL, stat = "sf_coordinates", position = "identity", ..., parse = FALSE, nudge_x = 0, nudge_y = 0, check_overlap = FALSE, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, fun.geometry = NULL) stat_sf(mapping = NULL, data = NULL, geom = "rect", position = "identity", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...)
xlim | Limits for the x and y axes. |
---|---|
ylim | Limits for the x and y axes. |
expand | If |
crs | Use this to select a specific coordinate reference system (CRS). If not specified, will use the CRS defined in the first layer. |
datum | CRS that provides datum to use when generating graticules |
label_graticule | Character vector indicating which graticule lines should be labeled
where. Meridians run north-south, and the letters This parameter can be used alone or in combination with |
label_axes | Character vector or named list of character values
specifying which graticule lines (meridians or parallels) should be labeled on
which side of the plot. Meridians are indicated by This parameter can be used alone or in combination with |
ndiscr | number of segments to use for discretising graticule lines; try increasing this when graticules look unexpected |
default | Is this the default coordinate system? If |
clip | Should drawing be clipped to the extent of the plot panel? A
setting of |
mapping | Set of aesthetic mappings created by |
data | The data to be displayed in this layer. There are three options: If A A |
stat | The statistical transformation to use on the data for this layer, as a string. |
position | Position adjustment, either as a string, or the result of a call to a position adjustment function. |
na.rm | If |
show.legend | logical. Should this layer be included in the legends?
You can also set this to one of "polygon", "line", and "point" to override the default legend. |
inherit.aes | If |
... | Other arguments passed on to |
parse | If |
nudge_x | Horizontal and vertical adjustment to nudge labels by. Useful for offsetting text from points, particularly on discrete scales. |
nudge_y | Horizontal and vertical adjustment to nudge labels by. Useful for offsetting text from points, particularly on discrete scales. |
label.padding | Amount of padding around label. Defaults to 0.25 lines. |
label.r | Radius of rounded corners. Defaults to 0.15 lines. |
label.size | Size of label border, in mm. |
fun.geometry | A function that takes a |
check_overlap | If |
geom | The geometric object to use display the data |
geom_sf()
uses a unique aesthetic: geometry
, giving an
column of class sfc
containing simple features data. There
are three ways to supply the geometry
aesthetic:
Do nothing: by default geom_sf()
assumes it is stored in
the geometry
column.
Explicitly pass an sf
object to the data
argument.
This will use the primary geometry column, no matter what it's called.
Supply your own using aes(geometry = my_column)
Unlike other aesthetics, geometry
will never be inherited from
the plot.
coord_sf()
ensures that all layers use a common CRS. You can
either specify it using the CRS
param, or coord_sf()
will
take it from the first layer that defines a CRS.
if (requireNamespace("sf", quietly = TRUE)) { nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE) ggplot(nc) + geom_sf(aes(fill = AREA)) # If not supplied, coord_sf() will take the CRS from the first layer # and automatically transform all other layers to use that CRS. This # ensures that all data will correctly line up nc_3857 <- sf::st_transform(nc, "+init=epsg:3857") ggplot() + geom_sf(data = nc) + geom_sf(data = nc_3857, colour = "red", fill = NA) # Unfortunately if you plot other types of feature you'll need to use # show.legend to tell ggplot2 what type of legend to use nc_3857$mid <- sf::st_centroid(nc_3857$geometry) ggplot(nc_3857) + geom_sf(colour = "white") + geom_sf(aes(geometry = mid, size = AREA), show.legend = "point") # You can also use layers with x and y aesthetics: these are # assumed to already be in the common CRS. ggplot(nc) + geom_sf() + annotate("point", x = -80, y = 35, colour = "red", size = 4) # Thanks to the power of sf, a geom_sf nicely handles varying projections # setting the aspect ratio correctly. library(maps) world1 <- sf::st_as_sf(map('world', plot = FALSE, fill = TRUE)) ggplot() + geom_sf(data = world1) world2 <- sf::st_transform( world1, "+proj=laea +y_0=0 +lon_0=155 +lat_0=-90 +ellps=WGS84 +no_defs" ) ggplot() + geom_sf(data = world2) # To add labels, use geom_sf_label(). ggplot(nc_3857[1:3, ]) + geom_sf(aes(fill = AREA)) + geom_sf_label(aes(label = NAME)) }