Know India through Visualisations – 1

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I’m going to produce just a couple of charts, a teaser of sorts in this post. In the forthcoming posts I’ll dig deeper.

I was amazed with the existing list of R packages to work with spatial data, without needing to get into much of the technical details. Various R packages I’ve used are described along with the code.

I’ve obtained the state level power supply position data for the November 2004 (just a random choice) from the data portal of the government of India website. The spatial data for India with state boundaries was obtained from Global Administrative Areas website.



Above plot is generated using spplot() function from sp package, below is a similar plot generated using ggplot() function from ggplot2 package. In the plot, darker shades of blue signify higher severity of electricity shortage and lighter shades signify lower severity as can be seen from the legend. The numbers in the legend are in MU i.e. Million Units (equivalent to gigawatt hour).


The advantage of using ggplot() is that I can add additional layers onto this map easily. For e.g. I can add labels of the states as can be seen below.


The R Code for this post is shown below and can also be found on this GitHub Gist
######## Packages ########
checkAndDownload<-function(packageNames) {
for(packageName in packageNames) {
if(!isInstalled(packageName)) {
install.packages(packageName,repos="http://lib.stat.cmu.edu/R/CRAN")
}
library(packageName,character.only=TRUE,quietly=TRUE,verbose=FALSE)
}
}
isInstalled <- function(mypkg){
is.element(mypkg, installed.packages()[,1])
}
packages <- c("sp","ggplot2","plyr","rgeos","maptools","sqldf","RColorBrewer")
checkAndDownload(packages)
# 'sp' a package for spatial data
# 'plyr' required for fortify which converts 'sp' data to
#polygons data to be used with ggplot2
# 'rgeos' required for maptools
# 'maptools' required for fortify - region
################ Data Input ##############
#get the nation-wide map data with state boundaries
con <- url("http://biogeo.ucdavis.edu/data/gadm2/R/IND_adm1.RData")
load(con)
close(con)
#get the data from indian government data website about powerSuply position for a particular month
data_url = "http://data.gov.in/access-point-download-count?url=http://data.gov.in/sites/default/files/powerSupplyNov04.csv&nid=34321"
nov04 <- read.table(
file=data_url,
header=TRUE,
sep=",",
as.is=TRUE)
power = nov04
#get the state codes file
#(data dictionary with indian states mapped to a 2 letter state code)
stateCodes <- read.table(
file="D:/JustAnotherDataBlog/Data/IndiaStateCodes.csv",
header=TRUE,
sep=",",
as.is=TRUE)
########## Adhoc Data cleaning #########
#renaming the important columns
colnames(power)
colnames(power)[1] = "State"
colnames(power)[2] = "Demand"
colnames(power)[3] = "Supplies"
colnames(power)[4] = "Net Surplus"
colnames(power)
#adjusting power supply position in these states based on geographic area
#area numbers obtained from wikipedia
WB_Area <- 88752
Sikkim_Area <- 7096
Jharkhand_Area <-79714
WB_Sikkim_Prop <- WB_Area / (WB_Area + Sikkim_Area)
WB_Jharkhand_Prop <- WB_Area / (WB_Area + Jharkhand_Area)
#1.West Bengal and Sikkim to be split in some ratio:ratio of areas
WB1 <- power[power[, "State" ]== "W B + Sikkim" , -1] * WB_Sikkim_Prop
SK <- power[power[, "State" ]== "W B + Sikkim" , -1] - WB1
#2.DVC numbers to be divided between Jharkhand and West Bengal: by ratio of areas
WB2 <- power[power[, "State" ]== "DVC" , -1] * WB_Jharkhand_Prop
power[power[, "State" ]== "Jharkhand" , -1] <- power[power[, "State" ]== "Jharkhand" , -1] +
power[power[, "State" ]== "DVC" , -1] - WB2
WB = WB1 + WB2
#3. Tripura: not present in some of the datasets
#4. Andaman and Nicobar, Lakshdweep not part of the analysis
power = rbind(power,cbind(State="West Bengal",WB),cbind(State="Sikkim",SK))
######### Preparing data for visualisation ###########
#merge power data with state codes file
power_stateCodes <- sqldf("select a.*,b.* from stateCodes as a inner join power as b on a.State = b.State")
#cross check
sum(power_stateCodes$Demand) == power[power[, "State" ]== "All India" , 2]
power_stateCodes$Net_check = power_stateCodes$Supplies - power_stateCodes$Demand
sum(power_stateCodes$Net_check - power_stateCodes$Net_Surplus)
as.data.frame(gadm)
gadm@data
states <- as.data.frame(gadm@data$NAME_1)
colnames(states) ="State_gadm"
states_stateCodes <- sqldf("select a.*,b.* from states as a
left join stateCodes as b on a.State_gadm = b.State")
power_states <- sqldf("select a.State_gadm, a.Code, b.Demand,
b.Supplies, b.Net_Surplus from states_stateCodes as a
left join power_stateCodes as b on a.Code = b.Code")
power_states$log_Deficit <- log(-power_states$Net_Surplus+1)
breaks = quantile(power_states$log_Deficit,na.rm=TRUE)
breaks = 1 - exp(breaks)
power_states$Severity = cut(power_states$Net_Surplus,breaks,include.lowest =TRUE)
#with(power_states,power_states[Code == 'MH',])
#crosscheck as we can't merge using name
sum(gadm@data$NAME_1==power_states$State_gadm)==nrow(gadm@data)
gadm <- spCbind(gadm,power_states)
plotclr <- rev(brewer.pal(length(levels(gadm@data$Severity)),"Blues"))
#using spplot
png(file="D:/JustAnotherDataBlog/Plots/FirstPost_PS_Pos_Nov_04_Ind_spplot.png",width=500,height=400)
spplot(gadm, "Severity",
col.regions=plotclr
,main="India: Net Power Supply Position for Nov 2004 (MU)")#, col="transparent")
dev.off()
#using ggplot
india <- fortify(gadm, region = "NAME_1")
#india.df <- join(india, gadm@data, by="NAME_1") doesn't work because id cols are different
names(india)
temp <- gadm@data
india.df <- sqldf("select a.* ,b.* from india as a
left join temp as b on a.id = b.Name_1")#it's not case sensitive
S_Code <- aggregate(cbind(long, lat) ~ Code, data=india.df, FUN=function(x)mean(range(x)))
S_Code <-ddply(india.df, .(Code), function(df) kmeans(df[,1:2], centers=1)$centers)
png(file="D:/JustAnotherDataBlog/Plots/FirstPost_PS_Pos_Nov_04_Ind_ggplot.png",width=500,height=400)
p <- ggplot(india.df,aes(long,lat)) +
geom_polygon(aes(group=group,fill=Severity),color='white') +
geom_text(data=S_Code,aes(long,lat,label=Code), size=2.5) +
#geom_path(color="white") +
coord_equal() +
scale_fill_brewer() +
ggtitle("India: Net Power Supply Position for Nov 2004 (MU)")
p
dev.off()


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