Mapping the places I travelled using leaflet R package

In this I tried to map the places I vistied during my academics & job using the leaflet R package. Packages used: XML,plyr & leaflet

Install the above packages and load them

Preparing the data

library(XML)
library(plyr)
library(leaflet)
# Preparing the data

# character vector cities
cities <- c("Varanasi, India", "Jaipur, India", "Residency Road, Bangalore, India" ,"ITPL, Bangalore, India", "Phoenix, USA", 
            "Guadalajara, Mexico", "Marthahalli, Bangalore, India", "Melbourne, Australia","Bangalore, India")

# character vector description
desc = c("School @ St. John's School", "Graduation @ SKIT, Jaipur", "Job @ Think Ahead Advisory Services Ltd.", 
         "Job @ TCS Bang.", "Job @ TCS Phoenix", "Job @ TCS Mexico", "Job @ NICE Interactive Solutions", "Job @ NICE Systems Aus.","Job @ NICE Interactive Solutions")

We do not have the geocodes so will be using the Google’s map API to fetch the geocodes for places visited.

Let us make a function which would be called for each row in the character vector and return a dataframe with the place, correspoding latitude and longitude.

# Function to get the latitude and longitude
latlong <- function(place)
{
  theURL <- sprintf('http://maps.google.com/maps/api/geocode/xml?sensor=false&address=%s', place)
  
  doc <- xmlToList(theURL)
  
  data.frame(Place=place, 
             Latitude=as.numeric(doc$result$geometry$location$lat), 
             Longitude=as.numeric(doc$result$geometry$location$lng), 
             stringsAsFactors=FALSE)
}

Call the above function on the character vector cities. Note Google has an upper cap on how many geocodes you can fetch in a day.

places <- adply(cities,1,latlong)
str(places)

## 'data.frame':    9 obs. of  4 variables:
##  $ X1       : Factor w/ 9 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9
##  $ Place    : chr  "Varanasi, India" "Jaipur, India" "Residency Road, Bangalore, India" "ITPL, Bangalore, India" ...
##  $ Latitude : num  25.3 26.9 13 13 33.4 ...
##  $ Longitude: num  83 75.8 77.6 77.7 -112.1 ...

Make a dataframe with cities, lat , long and description to be used in maping

df = data.frame(places, desc, stringsAsFactors = F)
str(df)

## 'data.frame':    9 obs. of  5 variables:
##  $ X1       : Factor w/ 9 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9
##  $ Place    : chr  "Varanasi, India" "Jaipur, India" "Residency Road, Bangalore, India" "ITPL, Bangalore, India" ...
##  $ Latitude : num  25.3 26.9 13 13 33.4 ...
##  $ Longitude: num  83 75.8 77.6 77.7 -112.1 ...
##  $ desc     : chr  "School @ St. John's School" "Graduation @ SKIT, Jaipur" "Job @ Think Ahead Advisory Services Ltd." "Job @ TCS Bang." ...

Using leaflet for maping

mymap = leaflet() %>%
  addProviderTiles("CartoDB.Positron") %>%
  addProviderTiles("CartoDB.DarkMatter", 
                   options = providerTileOptions(opacity = 0.8)) %>%
  setView(5, 20, zoom=1) %>%
  # color and weight arguments for the color and weight of the line
  addPolylines(data=df, ~Longitude, ~Latitude, color = "white", 
               weight = 2, opacity = 0.6) %>%
  addCircleMarkers(data=df, ~Longitude, ~Latitude,  color = "#daa520", 
                   opacity = 0.6, radius = 2, popup = paste(cities, desc, sep="<br>"))

mymap

Pan and zoom can be adjusted

References: Blog post from Jared Lander

Mapping the places I travelled using leaflet R package

Abhinav