README.md

tileR

This repository contains a simple package which let's users create a simple slippy tile service from an sf object. It is intended for local testing with leaflet--particularly for relatively large sf objects.

Example

Assume you have a local geopackage called world.gpkg containing country outlines. We can make a basic WMS-like service by running:

library(sf)
library(tileR)
library(plumber)

world <- st_read(system.file("examples/world/data.gpkg", package = "tileR"))

# optonal--add some basic styling
value <- world[, "name"] |> st_drop_geometry() |> unlist(use.names = FALSE)
cols  <- rainbow(10)[sample(10, nrow(world), replace = TRUE)]

pal <- function(x) {
 cols[which(x == value)]
}

options <- plotoptions(
  pal = pal, value = "name"
)

create_service(world, "world", "world", options)

service <- plumber::pr("world/service.R")
pr_run(service)

This will start a service on a random port, and the service can be used in leaflet's addTiles function. For example, if the port is 5086, the URL template would be:

http://localhost:5086/world/{z}/{x}/{y}

We could display this in a leaflet map (in a different session) by running:

library(leaflet)

leaflet() |> 
  addTiles() |> 
  addTiles(urlTemplate = "http://localhost:5086/world/{z}/{x}/{y}")