In statnmap/cartomisc: Miscellaneous Tools for Spatial Data Manipulation and Analysis

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  out.width = "90%"
)

library(dplyr)
library(raster)
library(cartomisc)
library(ggplot2)

Extract part of the data with gplot_data

To draw multiple raster on the same ggplot2, or to draw raster after other objects (points, polygons, lines)

• data are extracted as a tibble
• data can then be added to a ggplot2 with geom_tile

# Read some data
slogo <- stack(system.file("external/rlogo.grd", package = "raster")) 
slogo

# Get partial raster data to plot in ggplot
r.gg <- gplot_data(slogo)

# Remove NA to reduce size of table
r.gg.nona <- r.gg %>% 
  filter(!is.na(value))

r.gg.nona

Plot with ggplot2

# Plot
ggplot(r.gg.nona) +
  geom_tile(aes(x = x, y = y, fill = value)) +
  scale_fill_gradient("Probability", low = 'yellow', high = 'blue') +
  facet_wrap(vars(variable)) +
  coord_equal()

Sun position

Calculate sun position for hillShade

sun_position <- sun_position(2019, 04, 26,
  hour = 12, min = 0, sec = 0,
  lat = 46.5, long = 6.5
)
sun_position

Use with hillShade

r <- raster(system.file("external/rlogo.grd", package = "raster"))
# slope and aspect
r_slope <- terrain(r, opt = "slope")
r_aspect <- terrain(r, opt = "aspect")
# hillshade
r_hillshade <- hillShade(r_slope, r_aspect, angle = sun_position$elevation, direction = sun_position$azimuth)
# plot
image(r)
image(r_hillshade, col = grey(seq(0, 1, 0.1), alpha = 0.5), add = TRUE)

statnmap/cartomisc documentation built on Aug. 20, 2020, 2:22 a.m.