In s-fleck/quickmap: Smartly Create Maps from R Objects

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
library(leaflet)
library(leafsync)

library(smartmap)

smartmap produces interactive maps from a variety of R objects with minimal coding required. This makes it great for previewing spatial data. It provides only three functions:

• smap(): The core function. Smartly create leaflet maps from R objects. Maps created with smap() contain two dialogues in the top right corner: one for switiching the background map and one for measuring distances and areas.
• smart_as_sf(): Applies the same heuristics as smap(), but returns sf objects instead.
• as_coord_matrix: Applies the same heuristics as smap(), but returns a numeric matrix with longitude and latitude instead.

Data frames

Viewing data.frames with longitude and latitude columns was the basic use case for which smartmap was created. The heuristics for automatically determining the geo-coordinate columns are simple, but should work for most use cases.

cities <- data.frame(
  city = c("Bregenz", "Eisenstadt", "Wiener Neustadt",
    "Graz", "Klagenfurt", "Linz", "Salzburg", "Innsbruck",
    "Vienna"),
  LaTituDE = c(47.51669707, 47.83329908, 47.81598187,
    47.0777582, 46.62034426, 48.31923281, 47.81047833,
    47.28040733, 48.20001528),
  lng = c(9.766701588, 16.53329747, 16.24995357,
    15.41000484, 14.3100203, 14.28878129, 13.0400203,
    11.4099906, 16.36663896),
  pop = c(26928, 13165, 60621.5, 242780, 88588, 265161.5,
    178274, 133840.5, 2065500),
  country = c("Austria", "Austria", "Austria", "Austria",
    "Austria", "Austria", "Austria", "Austria", "Austria"),
  province = c("Vorarlberg", "Burgenland",
    "Niederösterreich", "Steiermark", "Kärnten",
    "Oberösterreich", "Salzburg", "Tirol", "Wien")
)

print(cities)
smap(cities)

print(cities)
smap(cities)

source: [World Cities Database](https://simplemaps.com/data/world-cities)

Shapefiles

smap() also works with file system paths or urls to shapefiles. It even looks inside zip files if necessary!

smap("https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_0_countries.zip")

Point coordinates

Numeric vectors of length 2 are interpreted as longitude/latitude coordinate pairs. If you supply names, smap uses them to identify the correct order.

smap(c(16.422524, 48.185686))
smap(c(LAT = 48.185686, LoNgItuDE = 16.422524))

smap(c(LAT = 48.185686, LoNgItuDE = 16.422524))

Leaflet maps

You can call smap() on existing leaflet objects to add background tiles and a ruler for measuring distance

library(leaflet)
lf <- leaflet::leaflet(height=200) %>% 
  leaflet::addCircleMarkers(lng = 16.422524, lat = 48.185686)

lf
smap(lf)

library(leaflet)
lf <- leaflet::leaflet(height=200) %>% 
  leaflet::addCircleMarkers(lng = 16.422524, lat = 48.185686)

leafsync::sync(lf, smap(lf), sync.cursor = FALSE)

Simple features (sf)

Everyone who has worked with simple features will know that it is sometimes a bit awkward to convert between the different datatypes provided by the package (sf::sf, sf::sfc and sf::sfg). Toe remedy this smap() works natively with all three.

smap(sf::st_point(c(16.373311, 48.208482)))
smap(sf::st_sfc(sf::st_point(c(16.373311, 48.208482))))
smap(sf::st_sf(coords = sf::st_sfc(sf::st_point(c(16.373311, 48.208482))), crs = 4326))

smap(sf::st_sf(coords = sf::st_sfc(sf::st_point(c(16.373311, 48.208482))), crs = 4326))

s-fleck/quickmap documentation built on July 10, 2021, 6:55 a.m.