To create maps from tiles, maptiles
downloads, composes and displays
tiles from a large number of providers (e.g. OpenStreetMap, Stamen,
Esri, CARTO, or Thunderforest).
You can install the released version of maptiles from CRAN with:
install.packages("maptiles")
You can install the development version of maptiles
from GitHub with:
# install.packages("remotes")
remotes::install_github("riatelab/maptiles")
Note: maptiles
uses terra
which requires a recent version of GDAL (>= 3.0.4).
This is a basic example which shows you how to dowload and display OpenStreetMap tiles over North Carolina:
library(sf)
#> Linking to GEOS 3.9.0, GDAL 3.2.2, PROJ 7.2.1; sf_use_s2() is TRUE
library(maptiles)
# import North Carolina counties
nc_raw <- st_read(system.file("shape/nc.shp", package="sf"),
quiet = TRUE)
# Project to EPSG:3857
nc <- st_transform(nc_raw, "EPSG:3857")
# dowload tiles and compose raster (SpatRaster)
nc_osm <- get_tiles(nc, crop = TRUE)
# display map
plot_tiles(nc_osm)
# add Norh Carolina counties
plot(st_geometry(nc), col = NA, add = TRUE)
# add credit
mtext(text = get_credit("OpenStreetMap"),
side = 1, line = -1, adj = 1, cex = .9,
font = 3)
maptiles
gives access to a lot of tiles servers, but it is possible to
add others. The following example demonstrates the setting of a map
tiles server and how to cache the original tiles for future use:
# define the tile server parameters
osmpos <- list(src = 'CARTO.POSITRON',
q = 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
sub = c('a','b', 'c', 'd'),
cit = '© OpenStreetMap contributors © CARTO.')
# dowload tiles and compose raster (SpatRaster)
nc_osmpos <- get_tiles(x = nc, provider = osmpos, crop = TRUE,
cachedir = tempdir(), verbose = TRUE)
#> https://b.basemaps.cartocdn.com/light_all/7/34/50.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_34_50.png
#> https://d.basemaps.cartocdn.com/light_all/7/35/50.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_35_50.png
#> https://b.basemaps.cartocdn.com/light_all/7/36/50.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_36_50.png
#> https://a.basemaps.cartocdn.com/light_all/7/37/50.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_37_50.png
#> https://d.basemaps.cartocdn.com/light_all/7/34/51.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_34_51.png
#> https://d.basemaps.cartocdn.com/light_all/7/35/51.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_35_51.png
#> https://b.basemaps.cartocdn.com/light_all/7/36/51.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_36_51.png
#> https://a.basemaps.cartocdn.com/light_all/7/37/51.png => /tmp/RtmpFGXOix/CARTO.POSITRON/CARTO.POSITRON_7_37_51.png
#> Zoom:7
#> Data and map tiles sources:
#> © OpenStreetMap contributors © CARTO.
# display map
plot_tiles(nc_osmpos)
# display credits
mtext(text = osmpos$cit, side = 1, line = -1,
adj = 1, cex = .9, font = 3)
The following figure shows mini maps for most of the tiles providers available:
Original tiles use a projection known as “Web Mercator”, “WGS84 / Pseudo
Mercator”, “Google Mercator”, “EPSG:3857” or “EPSG:900913”. In most
cases get_tiles()
uses the projection of its x
argument to reproject
the tiles. If you wish to avoid any deformation induced by the
reprojection process, use “EPSG:3857” for x
projection.
All maps available through maptiles
are offered freely by various
providers. The only counterpart from the user is to properly display an
attribution text on the maps. get_credit()
displays a short credit
text to add on each map using the downloaded tiles.
Most of maptiles
code comes from getTiles()
and tilesLayer()
functions in cartography
.
It appears useful to me to have a package focused on the download and
display of map tiles only. On the technical side, it uses terra
instead of raster
for managing raster data.
There are many alternative packages that pursue the same objective as
maptiles
. Some focus on a specific map tiles provider (e.g. mapbox,
google, OpenStreetMap) or on a specific graphics device (ggplot2
). The
goal of maptiles
is to be flexible enough to allow the use of
different providers and to have a minimal number of robust and modern
dependencies. However, depending on the use case, one of following
packages may better suit your needs:
ceramic
ggmap
(ggplot2
focused)ggspatial
(ggplot2
focused, based onrosm
)mapboxapi
(mapbox)mapsapi
(google, based onRgoogleMaps
)OpenStreetMap
(requires Java)RgoogleMaps
(google)rosm
- …
Not to be confused with
tilemaps
, that “implements an
algorithm for generating maps, known as tile maps, in which each region
is represented by a single tile of the same shape and size.”