To create our interactive COVID map, we first download current COVID infrection data from

Data Link

According to the website, their data is updated daily, and as can be seen from the dates in the resulting .csv file, most of the data is for 6 Feb 2021, which is the current date as this is written.

• Load tidyverse for ease of manipulating data
• Load leaflet to create the interactive map
• Load the downloaded .csv file as a tibble

suppressMessages(library(tidyverse))
suppressMessages(library(leaflet))

COVID <- tibble(read.csv("./COVID-19_Cases_US.csv"))

• Filter out NA values for unassigned cases and non-US locations (mostly Puerto Rico)
• Create a column with county names along with the number of cases for marker popups
• Break number of cases into classes
• Color markers by number of cases

COVID <- COVID %>% filter(!is.na(Lat)) %>% filter(!is.na(Long_)) %>% 
     filter(Country_Region == "US")
COVID <- COVID %>% mutate(PopupInfo=paste(Admin2,Confirmed,sep=", "))
COVID <- COVID %>% mutate(InfClass=cut(Confirmed,breaks=
     c(0,1000,10000,50000,500000)))
COVID <- COVID %>% mutate(MyColor=factor(InfClass,labels=
     c("blue","green","yellow","red")))

• Create the map
• Add markers with popup information, clustering, and color by number of cases
• Add a legend

MyMap <- COVID %>% leaflet() %>% addTiles() %>% 
     addCircleMarkers(lat=~Lat,lng=~Long_,popup=~PopupInfo,
     clusterOptions=markerClusterOptions(),color=~MyColor) %>%             
     addLegend(labels=c("low","moderate","medium","high"),
     colors=c("blue","green","yellow","red"))

MyMap