Introduction

This article is an attempt to make .gifGraphics Interchangeable format to plot the time series data on one plot using animation.This makes the plot comparable over time for specific set of parameters. In other words, it is easy to understart and see the growth of certain parameter over time.

For instance, relationship between the gpd and life expectancy can be comapred among the nations over time as shown in the below .gif file,

GDP

GDP

The recent development of gganimate package had made this possible and easier. By the end of this article you will be able to make your own .gif file and create your own customeised frame to compare the different parameter on global or local scale.

Pre-requisite

Please install packages like

Software

Please ensure that your system is preloaded with Image Magick s/w in system program files folder. You may download and install the same from Image Magick

Get the Data

This article is an attempt to make .gif file on earthquake data from 1965-2016. It is better to plot yearwise global sesmic activity rather than a static look of all the values on the map. The data set for earthquake is available on kaggle. The data set contains data for global sesmic activity from 1965 to 2016. Please visit the above link and scroll down to get the .csv file.

Earthquake magnitude of 7 points on Richter Scale from 1965-2016

The dataset had been modified and only seismic value of 7 points on richter scale hd been considered for the study.

Data Manipulation

From the .csv file we have only selected few parameters for the sake of simplified calculation.

We are all set to start with codes in RStudio

R Codes

## Read the datatset and load the necessary packages
library(plyr)
library(dplyr)
library(ggmap)
library(ggplot2)
library(gganimate)
EQ=read.csv("eq.csv",stringsAsFactors = FALSE)
names(EQ)
## Only Select the data with magnitude greater than or equal to 7.
EQ<-EQ%>%filter(Magnitude>=7)

Split the Date into year,month and date

This is done in order ot get the frame which is important for the plot. In other words, The core of the approach is to treat frame (as in, the time point within an animation) as another aesthetic, just like x, y, size, color, or so on. Thus, a variable in your data can be mapped to frame just as others are mapped to x or y.

## Convert the dates into character in order to split the coloumn into "dd" "mm" "yy"" columns
EQ$Date<-as.character(EQ$Date)

## Split the date and create a list for the same

list<-strsplit(EQ$Date,"-")

## Convert the list into dataframe
library(plyr)
EQ_Date1<-ldply(list)
colnames(EQ_Date1)<-c("Day","Month","Year")

## Column bind with the main dataframe
EQ<-cbind(EQ,EQ_Date1)
names(EQ)
## Change the Date to numeric
EQ$Year=as.numeric(EQ$Year)

## Get the world map for plot and load the necessary package
library(ggmap)
world<-map_data("world")

## Remove the antartica region from the world map

world <- world[world$region != "Antarctica",]
map<-ggplot()+geom_map(data=world,map=world,aes(x=long,y=lat,map_id=region),color='#333300',fill='#663300')

#Plot points on world Map

p <- map + geom_point(data = EQ, aes(x = Longitude, y = Latitude, 
                                             frame = Year, 
                                            cumulative = TRUE,size=EQ$Magnitude), alpha = 0.3, 
                      size = 2.5,color="#336600")+
  geom_jitter(width = 0.1) +labs(title = "Earthquake above 7 point on richter scale")+theme_void()

# Plot .gif file using gganimate function

gganimate(p)
Earthquake

Earthquake

Mapping using Leaflet

There is another package for R Visualisation,“leaflet” and which is getting popular now a days because of its interactive feature. Users can actually zoom in and out to see the number of earthquake happened in an area by zooming in.

Leaflet package use the open street map which is more visually enhanced and easy to use. Please see leaflet for more information and also for step by step tutorial as well.

Let us Map the points for earthquake magnitude greater than 7,

Adding Markers

You can add markers to your map one at a time using the addMarkers() function by specifying the longitude and latitude,


addMarkers(lat=EQ$Latitude, lng=EQ$Longitude)

Here lat is the latitude and lng is the longitude. In out datamframe it is stored in the name of EQ\(Latitude and EQ\)Longitude.

Mapping Clusters

Sometimes you might have so many points on a map that it doesn’t make sense to plot every marker. In these situations leaflet allows you to plot clusters of markers using addMarkers,

(clusterOptions = markerClusterOptions())

When you zoom in to each cluster, the clusters will separate until you can see the individual markers.

library(leaflet)
 EQ%>%leaflet()%>%
 addTiles(group = "OSM (default)")%>%
 addMarkers(lat=EQ$Latitude, lng=EQ$Longitude,clusterOptions =markerClusterOptions(),popup= paste(EQ$Type,
                          "<br><strong>Magnitude: </strong>", EQ$Magnitude))

## Warning: package 'leaflet' was built under R version 3.3.3

Speed up projection in .gif using animation package

As we can see that plot has too many years from 1965 to 2016. Thus, in order to speed up the visual we can use the animation package to fast forward using ani.option()

library(animation)
ani.options(interval=0.15)
gganimate(p)
Earthquake_1.5x

Earthquake_1.5x

Conclusion

This article was an introductory tutorial to the world of animated map.Readers can try this and apply the same in other projects. Some of the example are,