Developing Data Products Assignment: R Markdown and Leaflet

Introduction

This document present the Peer-graded Assignment: R Markdown and Leaflet for the course “Developing Data Products” from Coursera.

The assignments requierments are the following:

Create a web page using R Markdown that features a map created with Leaflet.
Host your webpage on either GitHub Pages, RPubs, or NeoCities.
Your webpage must contain the date that you created the document, and it must contain a map created with Leaflet.

For this assignment I will present on the map the main locations from Timis County, Romania (European Union). I searched on the web spatial data and found information about population by locations on TEMPO-Online databes, of the Romanian National Institute of Statistics. Since the database cannot be filtered automatically, I downloaded the data in excel.

The dataset contain major locations from Timis County: cities, towns and communes (the villages that are administratively assigned to communes are not presented separately).

Load Packages and Data

# load packages
library(readxl)
library(leaflet)

#load the dataset
fileName <- 'PopulationByLocationTimisCounty_2020.xlsx'
TimisCountyData <- read_excel(fileName)

head(TimisCountyData)

## # A tibble: 6 x 6
##   Siruta Location  Type  Latitude Longitude Population
##    <dbl> <chr>     <chr>    <dbl>     <dbl>      <dbl>
## 1 155243 TIMISOARA City      45.8      21.2     325363
## 2 155350 LUGOJ     City      45.7      21.9      46409
## 3 155403 BUZIAS    Town      45.6      21.6       8389
## 4 156357 CIACOVA   Town      45.5      21.1       5453
## 5 155458 DETA      Town      45.4      21.2       7638
## 6 156801 FAGET     Town      45.8      22.2       7602

Preparing Icons and Popups

#Icon Image with Romania flag colors
RomaniaFlag <- makeIcon(iconUrl="https://www.exportgenius.in/global-data/img-flg/romania.png",iconWidth = 16, iconHeight = 16,iconAnchorX = 0, iconAnchorY = 36)

#Preparing popups to show location name and its population numbar

TimisPopup<-rep(NA,nrow(TimisCountyData))
for(i in 1:nrow(TimisCountyData)) {
TimisPopup[i]<-paste("Location","=",TimisCountyData[i,2],"<br/>","Population","=",TimisCountyData[i,6])}

Adding Multiple markers with Popups to our created map widget

Will use the piping notation “%>%” to chain the stage output as input to next stage:

leaflet() will transform our data frame “TimisCountyData” into leaflet map widget.
addTiles() will add graphics elements and layers to the map widget.
addMarkers() will take (Latitude & Longitude) values in previous output and add graphics elements layer (Icons + Popups) to map widget according to each spatial coordinates (Latitude & Longitude).

TimisCountyData %>%
  leaflet() %>%
  addTiles() %>%
  addMarkers(icon = RomaniaFlag, popup = TimisPopup)

## Assuming "Longitude" and "Latitude" are longitude and latitude, respectively

Drawing circles with its radius to show location population and adding legend

for this purpose we continue the chaining by adding circles using “addCircles()” function to indicate the population of each location by “radius =” argument.
the “color=” argument will color Capital city with blue, towns and communes with red.
add legend to show our coloring notation: (City->“blue” , Town & Commune ->“red”)

TimisCountyData %>%
  leaflet() %>%
  addTiles() %>%
  addMarkers(icon = RomaniaFlag, popup = TimisPopup) %>%
  addCircles(weight = 1, radius = sqrt(TimisCountyData$Population)*60,color = ifelse(TimisCountyData$Type=="City","blue", "red")) %>%
addLegend(labels = c("City","Town & Commune" ), colors = c("blue","red"))

## Assuming "Longitude" and "Latitude" are longitude and latitude, respectively
## Assuming "Longitude" and "Latitude" are longitude and latitude, respectively