Defines either an abstract geographic landscape (blank or containing user-defined landscape) or using a real Earth cartographic data from the Natural Earth project (https://www.naturalearthdata.com).

world(
  xrange,
  yrange,
  landscape = "naturalearth",
  crs = NULL,
  scale = c("small", "medium", "large")
)

Arguments

xrange

Two-dimensional vector specifying minimum and maximum horizontal range ("longitude" if using real Earth cartographic data)

yrange

Two-dimensional vector specifying minimum and maximum vertical range ("latitude" if using real Earth cartographic data)

landscape

Either "blank" (for blank abstract geography), "naturalearth" (for real Earth geography) or an object of the class sf defining abstract geographic features of the world

crs

EPSG code of a coordinate reference system to use for spatial operations. No CRS is assumed by default (NULL), implying an abstract landscape not tied to any real-world geographic region (when landscape = "blank" or when landscape is a custom-defined geographic landscape), or implying WGS-84 (EPSG 4326) coordinate system when a real Earth landscape was defined (landscape = "naturalearth").

scale

If Natural Earth geographic data is used (i.e. landscape = "naturalearth"), this parameter determines the resolution of the data used. The value "small" corresponds to 1:110m data and is provided with the package, values "medium" and "large" correspond to 1:50m and 1:10m respectively and will be downloaded from the internet. Default value is "small".

Value

Object of the class slendr_map, which encodes a standard spatial object of the class sf with additional slendr-specific attributes such as requested x-range and y-range.

Examples

# create a blank abstract world 1000x1000 distance units in size
blank_map <- world(xrange = c(0, 1000), yrange = c(0, 1000), landscape = "blank")

# it is possible to construct custom landscapes (islands, corridors, etc.)
island1 <- region("island1", polygon = list(c(10, 30), c(50, 30), c(40, 50), c(0, 40)))
island2 <- region("island2", polygon = list(c(60, 60), c(80, 40), c(100, 60), c(80, 80)))
island3 <- region("island3", center = c(20, 80), radius = 10)
archipelago <- island1 %>% join(island2) %>% join(island3)

custom_map <- world(xrange = c(1, 100), c(1, 100), landscape = archipelago)

# real Earth landscapes can be defined using freely-available Natural Earth
# project data and with the possibility to specify an appropriate Coordinate
# Reference System, such as this example of a map of Europe

real_map <- world(xrange = c(-15, 40), yrange = c(30, 60), crs = "EPSG:3035")
#> OGR data source with driver: ESRI Shapefile 
#> Source: "/private/var/folders/d_/hblb15pd3b94rg0v35920wd80000gn/T/Rtmp1tOPFb/naturalearth", layer: "ne_110m_land"
#> with 127 features
#> It has 3 fields