A space-time box plot of Spain’s TFR for 910 comarcas.

The idea behind spatial analysis is that space matters and near things are more similar: a variable measured in city A is (ideally) different from the same variable measured in city B. A simple way to get a feeling and to represent this hypothesis is through graphical visualization, usually a map(s).

TFRG_all_4years_Spain

However, when dealing with time series maps are cumbersome and  with sometimes some information is lost, such as the national average or path convergence. Box plots are a simple yet very effective way to synthesize a lot of information in one graph. The following plot depicts TFR over a 30 years period for 910 Spanish areas with respect to the national average value (thick black line in the middle of the boxes).

p <- ggplot(dat, aes(x=factor(YEAR), y=dat$TFR))
p <- p + geom_boxplot()
p <- p + scale_y_continuous(limits=c(0,2.5)) + scale_x_discrete("YEAR", breaks=seq(1981,2011,by=5))

TFRG

A ggmap of 2015 Israeli elections by city

IL_el_percThe recent Israeli elections are a reminder of how Demography and Space play a crucial role in the outcome of the 20th Knesset. For more insight, read the full Demotrends blog post by Ashira Menashe-Oren the demographics of the Israeli electorate here. The map has been done using ggmap and ggplot, two simple mapping tools I really like. If you are interested in the code, below you can find the relative syntax and data.

To start upload the libraries:

library(maptools) #reads the shape file 
library(ggmap) 
library(ggplot2)

Download the shape file (I normally use Diva-GIS website) and read it:

map.ogr<- readOGR(".","ISR_adm1")

Data set:

df <- structure(list(lon = c(35.148529, 35.303546, 34.753934, 34.781768,34.989571, 34.824785, 34.808871, 34.883879, 34.844675, 34.90761, 35.010397, 34.871326, 35.21371, 34.655314, 34.887762, 34.792501, 34.574252, 34.791462, 34.748019, 34.787384, 34.853196, 34.811272, 34.919652, 34.888075, 35.098051, 35.119773, 34.872938, 34.835226, 34.988099, 35.002462), lat = c(32.517127, 32.699635, 31.394548, 32.0853, 32.794046, 32.068424, 32.072176, 32.149961, 32.162413, 32.178195, 31.890267, 32.184781, 31.768319, 31.804381, 32.084041, 31.973001, 31.668789, 31.252973, 32.013186, 32.015833, 32.321458, 31.892773, 32.434046, 31.951014, 33.008536, 32.809144, 31.931566,32.084932, 31.747041, 31.90912), City = structure(c(30L, 19L,24L, 29L, 9L, 25L, 7L, 11L, 10L, 14L, 16L, 23L, 13L, 1L, 21L,28L, 2L, 4L, 3L, 12L, 20L, 27L, 8L, 15L, 18L, 22L, 26L, 6L, 5L, 17L), .Label = c("Ashdod", "Ashkelon", "Bat yam", "Beersheva",  "Beit  Shemesh", "Bnei brak", "Giv'atayim", "Hadera", "Haifa",  "Herzliyya", "Hod HaSharon", "Holon", "Jerusalem", "Kefar Sava",  "Lod", "Modi'in - Makkabbim - Re'ut", "Modi'in Illit", "Nahariyya", "Nazareth ", "Netanya", "Petach Tikva", "Qiryat Atta", "Ra'annana",  "Rahat", "Ramat gan", "Ramla", "Rehovot", "Rishon", "Tel-Aviv",  "Umm Al-Fahm"), class = "factor"), most.votes = c(96.28, 91.41,  87.62, 34.03, 24.98, 30.93, 40.1, 38.77, 34.2, 34.66, 28.95,  32.75, 23.9, 30.96, 27.87, 29.78, 39.31, 37.17, 32.88, 30.86,  33.14, 26.95, 31.77, 32.22, 34.25, 35.01, 39.1, 57.56, 27.89,  71.63), party = structure(c(1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L,  2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L), .Label = c("joint list", "labour", "likud", "yahadut hatora"), class = "factor")), .Names = c("lon", "lat",  "City", "most.votes", "party"), class = "data.frame", row.names = c(NA,  -30L)) 

get the map using get_map

gmap <- get_map(location=c(34.2,29.4,36,33.5),zoom=7,source="stamen",maptype="watercolor")

and plot the map:


ggmap(gmap)+ 

geom_polygon(aes(x = long, y = lat, group=id), data = map.ogr, color ="blue", fill ="white", alpha = .8, size = .4)+ 

geom_point(aes(x=lon,y=lat,color=party,size=most.votes),data=df)+ scale_colour_discrete("Coalition", labels = c("Joint List", 
"Labour","Likud","United Torah Judaism"), breaks = c("joint list", 
"labour","likud","yahadut hatora")) +  
scale_size_continuous("Coalition", labels = c("Joint List",
 "Labour","Likud","United Torah Judaism"), breaks = c("joint list", 
"labour","likud","yahadut hatora"), range=c(10,15), guide = FALSE)+ 
theme(axis.text=element_text(size=18), 
plot.title=element_text(size=rel(3)), 
legend.key = element_rect(fill = "white"), 
legend.background =element_rect("white"), 
legend.text = element_text(size = 25), 
legend.title = element_text(size = 25))+ 
guides(colour = guide_legend(override.aes = list(size=8)))+  
labs(x="",y="")

IL_el_perc_city_names_color If you want to add city names you can use the “annotate” option, adding the code below after guides(...)+. I have modified the coordinates to avoid overlapping of labels and colored names to match the color of the winner party.

annotate("text", x=c(35.14853+ 0.2,35.21371+0.15,35.00246+ 0.15,34.79146+0.15, 34.98957-0.08,34.78177-0.14), 
y=c(32.51713,31.76832,31.90912,31.25297, 32.79405,32.08530),
size=5,font=3, 
label=c("Umm Al-Fahm","Jerusalem","Modin  Illit",
"Beersheva","Haifa","Tel Aviv"), 
color=c("darkred","blue4","deeppink4", "blue4",
"springgreen4","green4"))+

For beginners I highly recommend ggplot2 mailing list, a great and shame-free place to learn.

Location, location, location! Why space matters in demography and why we should care.

Read my first contribution to the Demotrends blog! and don’t forget to like Demotrends either in facebook or twitter 🙂
Of course all graphics have been realized in R (maptools library and a bunch of others).
Location, location, location! Why space matters in demography and why we should care..