Offline R map with RggogleMap and Leaflet

Question

I'm trying to create an interactive offline map of Canada in R After doing a bit of searching, RgoogleMaps and Leaflet seems like the best option. I followed the code here: R Leaflet Offline Map Tiles Not Loading

Here is my code:

setwd("C:/Users/user/Documents")
library(servr)
library(RgoogleMaps)

# Load the tiles in working_folder/mapTiles/OSM/
for (zoom in 2:13)
  GetMapTiles("Canada", zoom = zoom,
             nTiles = round(c(20,20)/(17-zoom)))


# Start serving working folder on port 8000 in demon mode
deamon_id <- servr::httd(port = 8000, daemon = TRUE)

# Plot with leaflet
library(leaflet)
m = leaflet() %>% 
  addTiles( urlTemplate = 
     "http:/localhost:8000/mapTiles/OMS/{z}_{x}_{y}.png")
m = m %>% leaflet::setView(-76, 45 , zoom = 5)
m = m %>% leaflet::addMarkers(-76, 45 )
m

# Stop serving
servr::daemon_stop(deamon_id)

Hovever, when I zoom in/out on the map, grey tiles appear where they wern't before:

This zoomed in image shows a grey tile over toronto

But,

This more zoomed-out image shows toronto

Any ideas on whats going wrong? Thank you!

Answer 1

nTiles = round(c(20,20)/(17-zoom)) This statement won't work consistently. If you want to get the map of Canada, instead of specifying nTiles, you can specify boundary like this: lonR = c(-142,-52),latR = c(41,84)