rasterpic is a tiny package with one single goal: to transform an image into a spatial raster.
Installation
Install rasterpic
from CRAN:
install.packages("rasterpic")
You can install the developing version of rasterpic with:
devtools::install_github("dieghernan/rasterpic")
Alternatively, you can install rasterpic using the r-universe:
# Enable this universe
options(repos = c(
dieghernan = "https://dieghernan.r-universe.dev",
CRAN = "https://cloud.r-project.org"
))
install.packages("rasterpic")
Example
This package allows you to create cool maps by using a wide variety of objects:
Spatial object of the sf package:
sf
,sfc
,sfg
orbbox
.Spatial objects of the terra package:
SpatRaster
,SpatVector
,SpatExtent
.A vector of coordinates with the form
c(xmin, ymin, xmax, yman)
An example using a sf
object:
library(rasterpic)
library(sf)
library(terra)
# The flag of the United Kingdom
img <- system.file("img/UK_flag.png",
package = "rasterpic"
)
uk <- st_read(
system.file("gpkg/UK.gpkg",
package = "rasterpic"
),
quiet = TRUE
)
# Rasterize!
uk_flag <- rasterpic_img(uk, img)
uk_flag
#> class : SpatRaster
#> dimensions : 400, 800, 3 (nrow, ncol, nlyr)
#> resolution : 5398.319, 5398.319 (x, y)
#> extent : -2542183, 1776472, 6430573, 8589900 (xmin, xmax, ymin, ymax)
#> coord. ref. : WGS 84 / Pseudo-Mercator (EPSG:3857)
#> source(s) : memory
#> names : lyr.1, lyr.2, lyr.3
#> min values : 0, 13, 34
#> max values : 255, 255, 255
# Plot it!
plotRGB(uk_flag)
plot(st_geometry(uk),
add = TRUE,
col = adjustcolor("blue",
alpha.f = 0.5
)
)
We can also play with other parameters, as well as modifying the alignment of the image with respect to the object:
# Align, crop and mask
uk_flag2 <- rasterpic_img(uk, img, halign = 0.2, crop = TRUE, mask = TRUE)
plot(st_geometry(uk), axes = TRUE)
plotRGB(uk_flag2, add = TRUE)
plot(st_geometry(uk), col = NA, border = "black", add = TRUE)
You can plot the rasters with ggplot2 + tidyterra:
library(ggplot2)
library(tidyterra)
ggplot(uk) +
geom_spatraster_rgb(data = uk_flag2) +
geom_sf(fill = NA)
Image formats admitted
rasterpic can parse the following image formats:
-
png
files. -
jpg/jpeg
files. -
tif/tiff
files.
Citation
To cite ‘rasterpic’ in publications use:
Hernangomez D (2023). rasterpic: Create a Spatial Raster from Plain Images. https://doi.org/10.5281/zenodo.5910095, https://dieghernan.github.io/rasterpic/
A BibTeX entry for LaTeX users is:
@Manual{R-rasterpic,
= {rasterpic: Create a Spatial Raster from Plain Images},
title = {Diego Hernangómez},
author = {2023},
year = {0.2.1},
version = {10.5281/zenodo.5910095},
doi = {https://dieghernan.github.io/rasterpic/},
url = {Create a spatial raster, as the ones provided by terra, from regular pictures.},
abstract }
Contribute
Check the GitHub page for source code.