make_raster_map: Plot a georeferenced raster on a map

In BIO-RSG/oceancolouR: Various Functions for Satellite and Data Analysis

Plot a georeferenced raster on a map

Description

Plot a raster on a map. If a RasterStack is provided instead, facet_wrap will be used to plot the raster layers on separate maps, and nrow specifies the number of rows of maps (note: they will be plotted by row rather than by column). The names of the raster layers in the stack will be used as titles, and the maps will all use the same color scale.

Usage

make_raster_map(
  rast,
  title = NULL,
  xlim = NULL,
  ylim = NULL,
  xbreaks = NULL,
  ybreaks = NULL,
  xlabs = NULL,
  ylabs = NULL,
  sec.axis.x = NULL,
  sec.axis.y = NULL,
  col_limits = NULL,
  cm = colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan", "#7FFF7F", "yellow",
    "#FF7F00", "red", "#7F0000"))(100),
  set_extremes = FALSE,
  na.value = "transparent",
  rast_alpha = 1,
  map_alpha = 0.8,
  map_fill = "grey",
  map_colour = "darkgrey",
  nrow = 1,
  show_legend = TRUE,
  ...
)

Arguments

rast	Georeferenced RasterLayer or RasterStack
title	Optional title of the map
xlim	Longitude limits. Set to NULL to let the function decide.
ylim	Latitude limits. Set to NULL to let the function decide.
xbreaks	x-axis (longitude) breaks/tick positions. Set to NULL to let the function decide.
ybreaks	x-axis (latitude) breaks/tick positions. Set to NULL to let the function decide.
xlabs	x-axis (longitude) labels to use. Set to NULL to let the function decide.
ylabs	y-axis (latitude) labels to use. Set to NULL to let the function decide.
sec.axis.x	Function to define secondary axis on opposite side of plot from x axis.
sec.axis.y	Function to define secondary axis on opposite side of plot from y axis.
col_limits	Color scale limits
cm	Color scale
set_extremes	TRUE/FALSE, should values outside the range in col_limits be set to the min/max? If not, they will be transparent. Ignored if col_limits=NULL
na.value	Color to use for NA values in raster
rast_alpha	Transparency of the raster on the map, 0-1
map_alpha	Transparency of landmasses on map, 0-1
map_fill	Colour of the landmasses in the map
map_colour	Colour of the outline of the landmasses in the map
nrow	Number of rows of plots, for raster stacks
show_legend	Display the raster legend next to the map?
...	Extra arguments to scale_fill_gradientn()

Value

Raster or grid of rasters on maps with coastlines.

Examples

library(terra)
library(ggplot2)
# use SGLI L2 data and make a terra raster
data("example02_GC1SG1_202109031518L33309_L2SG_IWPRK_2000")
pts <- example02_GC1SG1_202109031518L33309_L2SG_IWPRK_2000
rast <- rasterize(as.matrix(pts[,1:2]), rast(extent=terra::ext(c(range(pts$lon),range(pts$lat)))), pts$chl, fun=mean, na.rm=TRUE)
# plot it on the map
make_raster_map(rast,title=NULL,xlim=c(-95,-42),ylim=c(39,82),trans="log10") +
    theme(axis.title=element_blank(),
          legend.title=element_blank(),
          legend.margin=margin(0,0,0,0),
          legend.box.margin=margin(-10,0,-10,-10)) +
    guides(fill = guide_colourbar(title.hjust = 0,
                                  ticks.colour = "black",
                                  barwidth = unit(0.6, "cm"),
                                  barheight = unit(8, "cm"),
                                  frame.colour = "black"))

BIO-RSG/oceancolouR documentation built on April 30, 2024, 7:54 a.m.