Motivation

I am a longtime fan of the mapview package. I use it repeatedly during a typical R work session to quickly visualize and interact with spatial data. Most of my time in RStudio is spent writing a regular R script. If I want to see mapview’s interactive map in a larger window, I simply mouse over to the Viewer pane, and pop the map out using either the “Zoom” button or the “Show in new window” button.

I have lately been using RMarkdown more. Mapview works as expected in RMarkdown, but I was missing the ability to pop out the interactive map from the resulting html in full-screen. For example, the below map cannot be viewed in full screen:

library(mapview)
library(tidyverse)
breweries = mapview::breweries #bring to local env't
breweries %>% 
  mapview(layer.name = "breweries")

Full-screen mode with one mapview object

Fortunately, the leaflet.extras package has the addFullscreenControl function, but applying this function directly to a mapview object does not work, because this function expects a leaflet map:

library(leaflet)
library(leaflet.extras)
breweries %>% 
  mapview(layer.name = "breweries") %>% 
  leaflet.extras::addFullscreenControl() #does not work

In this issue (38), mapview’s author explains how to access the leaflet map component of the mapview object via @map. To my knowledge, this @map cannot be called at the end of a pipe, but we can create a mapview object first, access the leaflet map via @map, and then use leaflet.extras’ addFullscreenControl function. The following code does this, adding a full-screen control button to the top-left of the map:

mv_breweries = breweries %>% 
  mapview(layer.name = "breweries")

mv_breweries@map %>% 
  leaflet.extras::addFullscreenControl() #works

Full-screen mode with more than one mapview object

One other thing. Sometimes, it’s useful to add multiple layers to the same interactive map using the + operator, as described. To add full-screen control to mapview objects comprised of multiple mapview objects, we access the leaflet map via @map from the final mapview object (i.e., not each constituent mapview object).

For example, suppose we create one mapview object to visualize breweries founded before 1800 and another for those founded after. We can combine those two mapview objects using + and add full-screen control to the resulting mapview comprising both following the code above.

summary(breweries$founded)

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's 
##    1353    1693    1858    1805    1891    2013     144

mv_old_breweries = breweries %>% 
  filter(founded <1800) %>% 
  mapview(
    layer.name = "old breweries",
    col.regions = "orange",
    color = "orange")

mv_new_breweries = breweries %>% 
  filter(founded >=1800) %>% 
  mapview(
    layer.name = "new breweries",
    col.regions = "blue",
    color = "blue")

mv_old_and_new = mv_old_breweries + 
  mv_new_breweries

mv_old_and_new@map %>% 
  leaflet.extras::addFullscreenControl()

Again, the full-screen icon is on the top-left, allowing the user to interactively pop the map into full-screen mode.

Full-screen control with mapview in RMarkdown

Michael D. Garber

April 7th, 2022

Motivation

Full-screen mode with one mapview object

Full-screen mode with more than one mapview object