crstools.R
In crstools: Tools to Work with Projections

## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----setup, eval=FALSE--------------------------------------------------------
# devtools::install_github("EvolEcolGroup/crstools")

## ----get_s_america------------------------------------------------------------
library(rnaturalearth)
library(sf)
s_america_sf <- ne_countries(continent = "South America", returnclass = "sf")

## ----plot_s_america-----------------------------------------------------------
library(ggplot2)
ggplot() +
  geom_sf(data = s_america_sf) +
  theme_minimal()

## ----check_crs----------------------------------------------------------------
sf::st_crs(s_america_sf)

## ----check_crs_epsg-----------------------------------------------------------
sf::st_crs(s_america_sf)$proj4string

## -----------------------------------------------------------------------------
library(crstools)
s_am_equal_area <- suggest_crs(s_america_sf, distortion = "equal_area")

## -----------------------------------------------------------------------------
s_am_equal_area

## ----plot_s_america_equidist--------------------------------------------------
ggplot() +
  geom_sf(data = s_america_sf) +
  coord_sf(crs = s_am_equal_area$proj4) +
  theme_minimal()

## -----------------------------------------------------------------------------
ggplot(data = s_america_sf) +
  geom_sf() +
  geom_tissot() +
  coord_sf(crs = s_am_equal_area$proj4) +
  theme_minimal()

## -----------------------------------------------------------------------------
ggplot(data = s_america_sf) +
  geom_sf() +
  geom_tissot() +
  coord_sf(crs = "+proj=merc") +
  theme_minimal()

## -----------------------------------------------------------------------------
s_america_sf_equal_area <- sf::st_transform(s_america_sf, s_am_equal_area$proj4)
sf::st_crs(s_america_sf_equal_area)$proj4string

## ----plot_sa_equidist_proj----------------------------------------------------
ggplot() +
  geom_sf(data = s_america_sf_equal_area) +
  theme_minimal()

## ----get_raster_europe--------------------------------------------------------
library(terra)
library(pastclim)

# get example dataset from cran
set_data_path(on_CRAN = TRUE)

europe_r <- region_slice(
  time_bp = 0,
  bio_variables = c("bio01"),
  dataset = "Example",
  ext = region_extent$Europe
)

## -----------------------------------------------------------------------------
europe_r

## -----------------------------------------------------------------------------
terra::crs(europe_r)

## -----------------------------------------------------------------------------
terra::crs(europe_r, proj = TRUE)

## ----plot_raster_s_america----------------------------------------------------
library(tidyterra)
ggplot() +
  geom_spatraster(data = europe_r) +
  scale_fill_viridis_c(na.value = "transparent") +
  theme_minimal()

## -----------------------------------------------------------------------------
europe_r_equal_area <- suggest_crs(europe_r, distortion = "equal_area")
europe_r_equal_area

## ----plot_raster_europe_ea----------------------------------------------------
ggplot() +
  geom_spatraster(data = europe_r) +
  scale_fill_viridis_c(na.value = "transparent") +
  coord_sf(crs = europe_r_equal_area$proj4) +
  theme_minimal()

## -----------------------------------------------------------------------------
ggplot() +
  geom_spatraster(data = europe_r) +
  scale_fill_viridis_c(na.value = "transparent") +
  geom_tissot(data = europe_r) +
  coord_sf(crs = europe_r_equal_area$proj4) +
  theme_minimal()

## -----------------------------------------------------------------------------
ggplot() +
  geom_spatraster(data = europe_r) +
  scale_fill_viridis_c(na.value = "transparent") +
  geom_tissot(data = europe_r) +
  coord_sf(crs = "+proj=merc") +
  theme_minimal()

## -----------------------------------------------------------------------------
europe_r_equal_area <- terra::project(europe_r, europe_r_equal_area$proj4)
terra::crs(europe_r_equal_area, proj = TRUE)

## ----plot_raster_europe_ea_proj-----------------------------------------------
ggplot() +
  geom_spatraster(data = europe_r_equal_area) +
  scale_fill_viridis_c(na.value = "transparent") +
  theme_minimal()