geom_spat_contour {tidyterra} | R Documentation |
Plot SpatRaster
contours
Description
These geoms create contours of SpatRaster
objects. To specify a valid
surface, you should specify the layer on aes(z = layer_name)
, otherwise all
the layers would be consider for creating contours. See also Facets
section.
The underlying implementation is based on ggplot2::geom_contour()
.
geom_spatraster_contour_text()
creates
labeled contours and it is implemented on top of isoband::isolines_grob()
.
Usage
geom_spatraster_contour(
mapping = NULL,
data,
...,
maxcell = 5e+05,
bins = NULL,
binwidth = NULL,
breaks = NULL,
na.rm = TRUE,
show.legend = NA,
inherit.aes = TRUE
)
geom_spatraster_contour_text(
mapping = NULL,
data,
...,
maxcell = 5e+05,
bins = NULL,
binwidth = NULL,
breaks = NULL,
size.unit = "mm",
label_format = scales::label_number(),
label_placer = isoband::label_placer_minmax(),
na.rm = TRUE,
show.legend = NA,
inherit.aes = TRUE
)
geom_spatraster_contour_filled(
mapping = NULL,
data,
...,
maxcell = 5e+05,
bins = NULL,
binwidth = NULL,
breaks = NULL,
na.rm = TRUE,
show.legend = NA,
inherit.aes = TRUE
)
Arguments
mapping |
Set of aesthetic mappings created by |
data |
A |
... |
Other arguments passed on to
|
maxcell |
positive integer. Maximum number of cells to use for the plot. |
bins |
Number of contour bins. Overridden by |
binwidth |
The width of the contour bins. Overridden by |
breaks |
One of:
Overrides |
na.rm |
If |
show.legend |
logical. Should this layer be included in the legends?
|
inherit.aes |
If |
size.unit |
How the |
label_format |
One of:
|
label_placer |
Function that controls how labels are placed along
the isolines. Uses |
Value
A ggplot2 layer
terra equivalent
Aesthetics
geom_spatraster_contour()
/ geom_spatraster_contour_text()
understands
the following aesthetics:
-
linewidth
geom_spatraster_contour_text()
understands also: -
label
-
family
-
fontface
Additionally, geom_spatraster_contour_filled()
understands also the
following aesthetics, as well as the ones listed above:
-
subgroup
Check ggplot2::geom_contour()
for more info on contours and
vignette("ggplot2-specs", package = "ggplot2")
for an overview of the
aesthetics.
Computed variables
These geom computes internally some variables that are available for use as
aesthetics, using (for example) aes(color = after_stat(<computed>))
(see
ggplot2::after_stat()
).
-
after_stat(lyr)
: Name of the layer. -
after_stat(level)
: Height of contour. For contour lines, this is numeric vector that represents bin boundaries. For contour bands, this is an ordered factor that represents bin ranges. -
after_stat(nlevel)
: Height of contour, scaled to maximum of 1. -
after_stat(level_low)
,after_stat(level_high)
,after_stat(level_mid)
: (contour bands only) Lower and upper bin boundaries for each band, as well the mid point between the boundaries.
Dropped variables
-
z
: After contouring, thez
values of individual data points are no longer available.
Coords
When the SpatRaster
does not present a crs (i.e.,
terra::crs(rast) == ""
) the geom does not make any assumption on the
scales.
On SpatRaster
that have a crs, the geom uses ggplot2::coord_sf()
to
adjust the scales. That means that also the
SpatRaster
may be reprojected.
Facets
You can use facet_wrap(~lyr)
for creating a faceted plot by each layer of
the SpatRaster
object. See ggplot2::facet_wrap()
for details.
See Also
The metR package also provides a set of alternative functions:
Other ggplot2 utils:
autoplot.Spat
,
fortify.Spat
,
geom_spatraster()
,
geom_spatraster_rgb()
,
ggspatvector
,
stat_spat_coordinates()
Examples
library(terra)
# Raster
f <- system.file("extdata/volcano2.tif", package = "tidyterra")
r <- rast(f)
library(ggplot2)
ggplot() +
geom_spatraster_contour(data = r)
# Labelled
ggplot() +
geom_spatraster_contour_text(
data = r, breaks = c(110, 130, 160, 190),
color = "grey10", family = "serif"
)
ggplot() +
geom_spatraster_contour(
data = r, aes(color = after_stat(level)),
binwidth = 1,
linewidth = 0.4
) +
scale_color_gradientn(
colours = hcl.colors(20, "Inferno"),
guide = guide_coloursteps()
) +
theme_minimal()
# Filled with breaks
ggplot() +
geom_spatraster_contour_filled(data = r, breaks = seq(80, 200, 10)) +
scale_fill_hypso_d()
# Both lines and contours
ggplot() +
geom_spatraster_contour_filled(
data = r, breaks = seq(80, 200, 10),
alpha = .7
) +
geom_spatraster_contour(
data = r, breaks = seq(80, 200, 2.5),
color = "grey30",
linewidth = 0.1
) +
scale_fill_hypso_d()