Week16: Breakout with Leaflet

Loading packages

Each member of the group should have installed and loaded the leaflet package

#install.packages("leaflet")
library("leaflet")

Each member of your group finds latitude & longitude:

Go to https://www.google.com/maps, click twice on the map (or right-click, then select “What’s here?”) until the grey marker and box appears (as in below) that lists your latitude and longitude:

Copy the Y, X location (e.g. 54.768244, -1.577359) and paste it into the table

##Gathering group data in a dataframe

name<-c("Monica","Andrew Baldwin","Greta","James Bond","Charles Darwin","Queen Elizabeth","J.K. Rowling","Another famous person")
location<-c("Durham","Newcastle","Derby","Durham","Durham","Durham","Durham","Durham")
latitude <- c(42.944753, 54.977768, 52.9258854, 54.775022, 54.77627, 54.779059, 54.777864,54.769299)
longitude <- c(-78.841205, -1.615672, -1.5232818, -1.585936, -1.5836173, -1.579716, -1.581218, -1.568980)

groupdf <- data.frame(name, location, latitude, longitude)

groupdf

##                    name  location latitude  longitude
## 1                Monica    Durham 42.94475 -78.841205
## 2        Andrew Baldwin Newcastle 54.97777  -1.615672
## 3                 Greta     Derby 52.92589  -1.523282
## 4            James Bond    Durham 54.77502  -1.585936
## 5        Charles Darwin    Durham 54.77627  -1.583617
## 6       Queen Elizabeth    Durham 54.77906  -1.579716
## 7          J.K. Rowling    Durham 54.77786  -1.581218
## 8 Another famous person    Durham 54.76930  -1.568980

Looking at examples

Use RStudio to create a map with leaflet that plots all of the locations in your dataframe as points.

Here is the guide to Leaflet in R: https://rstudio.github.io/leaflet

Use the example of Quakes here https://rstudio.github.io/leaflet/markers.html

Here is the example of quakes from the link above:

data(quakes)  #replace “quakes” with the name of your group

# You don’t want only the first 20 rows of the quakes dataset, but what do you want?
leaflet(data = quakes[1:20,]) %>% addTiles() %>%
  addMarkers(~long, ~lat, popup = ~as.character(mag), label = ~as.character(mag))

Now modify it with your own code

leaflet(data = groupdf) %>%
  addTiles() %>%
  addMarkers(~longitude, ~latitude, popup = ~as.character(name))

If you are uncomfortable using pipes, this is the same as

m<- leaflet(data = groupdf)
m<- addTiles(m)
m<- addMarkers(m, ~longitude, ~latitude, popup = ~as.character(name))
m

You may want to modify the aesthetics of your map

leaflet(data= groupdf) %>% addProviderTiles(providers$CartoDB.Positron) %>%
  addCircleMarkers(~longitude, ~latitude, popup = ~as.character(name))

Stay Tuned

Please visit the development page of the prettydoc package for latest updates and news. Comments, bug reports and pull requests are always welcome.