Introduction

The evolMap package provides an easy and flexible way to create interactive, time-evolving maps from spatial data in R. It is particularly useful for visualizing historical changes, events over time, or evolving geospatial datasets, using Leaflet as the underlying engine. Key features include:

• Integration with sf and GeoJSON for spatial data
• Support for time-aware markers and geometries
• Easy customization of base maps, tiles, and map styles
• Export of HTML-based maps to local directories for web use

This vignette demonstrates how to use evolMap to:

• Visualize a historical site (Pompeii) from GeoJSON data
• Animate event data (Ukraine war incidents) over time
• Change base map styles and render modes

Description

The evolMap package represents and manages information from a database on an interactive geographic map. It also allows you to view the evolution of added elements over time or through periods.

Components:

• Entities: Markers, Lines, Images, Shapes, Choropleths, Links.
• Information: Table, Name, Tooltip, Information Window.
• Utilities: Entity Search, Filter, Display Customization, Playback Controls, Bar Charts.

Example 1: Visualizing Pompeii Parcels from GeoJSON

library(evolMap)
library(sf)

Read geojson

# Source: https://github.com/scriptorivm/pompeii
domi <- st_read('https://raw.githubusercontent.com/scriptorivm/pompeii/master/geojson/domi.geojson')

domi[["info"]] <- paste0("<iframe src=\"",sub("http:","https:",domi[["N3"]]),"\"></iframe>")
domi[is.na(domi[["N3"]]),"info"] <- "Missing info"

Map creation and add information of geojson

You can specify initial coordinates and zoom level in create_map function

map <- create_map(center=c(40.750556,14.489722), zoom=16)
map <- add_entities(map,domi,info="info")
plot(map, directory = "pompeii")

## The graph has been generated in the "/tmp/Rtmp4sdAKa/Rbuild8c8521ea2/evolMap/vignettes/pompeii" path.

Change Base Map Provider

# https://leaflet-extras.github.io/leaflet-providers/preview/
map <- create_map(center=c(40.750556,14.489722), zoom=16, provider="OpenStreetMap.HOT")
map <- add_entities(map,domi,info="info")
plot(map, directory = "pompeii_provider")

## The graph has been generated in the "/tmp/Rtmp4sdAKa/Rbuild8c8521ea2/evolMap/vignettes/pompeii_provider" path.

Example 2: Ukraine War — Evolving Event Map

# Source: https://ukraine.bellingcat.com/
data <- read.csv(system.file("extdata", "ukr-civharm-2023-02-27.csv",
        package="evolMap"))
data[["date"]] <- as.Date(data[["date"]],"%m/%d/%Y")

data[["type"]] <- NA
for(i in seq_len(nrow(data))){
  if(data[i,"associations"]!=""){
    data[i,"type"] <- unlist(strsplit(unlist(strsplit(data[i,"associations"],","))[1],"="))[2]
  }
}

map <- create_map(center=c(49.3402,31.9146),zoom=6.75)
map <- add_markers(map, data, color = "type",
  latitude = "latitude", longitude = "longitude",
  start = "date")
plot(map, dir="ukraine")

## The graph has been generated in the "/tmp/Rtmp4sdAKa/Rbuild8c8521ea2/evolMap/vignettes/ukraine" path.

Example: Change Map Style with mode = 2

map <- create_map(center=c(49.3402,31.9146),zoom=6.75, mode=2)
map <- add_markers(map, data, color = "type",
  latitude = "latitude", longitude = "longitude",
  start = "date")
plot(map, dir="ukraineNew")

## The graph has been generated in the "/tmp/Rtmp4sdAKa/Rbuild8c8521ea2/evolMap/vignettes/ukraineNew" path.

Summary

The evolMap package enables:

• Easy loading and visualization of geospatial data
  
• Support for both static features and time-evolving markers
  
• Integration with various map tile providers and styles
  
• HTML export for sharing maps online or offline