Creating maps in R just like the way rworldmap does but for specific country with provinces

Question

I use the rworldmap package with WorldBank Data and I enjoy it. I want to plot maps for Iran, with data related to each province. What are the steps to do that? I know we can plot maps like that in R for some countries like US but not for all countries.

Radbourne

You might be better off downloading some GIS shapefile data for Iran and then using one of the spatial packages to plot that in R - see here for the a file that might suit your purposes: gadm.org/download – Mortify

Answer 1

You can combine rworldmap with the great suggestion from @jazzurro of using raster to get GADM boundaries.

I suspect your main difficulty might be getting the province names to match between your data and the map.

The example below, uses defaults that you can change and just gives a different colour for each province.

library(raster)
library(rworldmap)
## 1 Get map of provinces (level 1 admin regions)
iranLevel1<- raster::getData("GADM", country = "Iran", level = 1)

## 2 join your [data] onto the map by specifying the join column in each
## this will report on any mis-matches between province names
#iranLevel1 <- rworldmap::joinData2Map([data],nameMap="iranLevel1",nameJoinIDMap="NAME_1",nameJoinColumnData=[insert])

## 3 plot map (change NAME_1 to the data you want to plot)
rworldmap::mapPolys(iranLevel1, nameColumnToPlot="NAME_1", addLegend=FALSE)

## 4 add text labels for provinces
text(iranLevel1, label="NAME_1", cex=0.7)

Note that joinData2Map(), mapPolys() are more generic equivalents of joinCountryData2Map(), mapCountryData().

Another way of doing this would be to use the choroplethr package.

Sediment

How to change color for specific province? – Prank

Answer 2

You can directly import GADM data using the raster package. Then, you can draw a map using ggplot2. When you download data, you can specify different level. Depending on this you see different boundaries.

library(raster)
library(ggplot2)

### Get data
iran<- getData("GADM", country = "Iran", level = 2)

### SPDF to DF
map <- fortify(iran)

### Draw a map
ggplot() +
geom_map(data = map, map = map, aes(x = long, y = lat, map_id = id, group = group))

EDIT

Seeing Andy's answer, I'd like to show how to add province names in ggplot2. This is something I learned from @hrbrmstr. The rworldmap package allows you to type less. The ggplot2 package still offers very nice graphics as well.

library(raster)
library(rgdal)
library(rgeos)
library(ggplot2)
library(dplyr)

### Get data
iran<- getData("GADM", country = "Iran", level = 1)

### SPDF to DF
map <- fortify(iran)

map$id <- as.integer(map$id)

dat <- data.frame(id = 1:(length(iran@data$NAME_1)), state = iran@data$NAME_1)
map_df <- inner_join(map, dat, by = "id")

# Find a center point for each province
centers <- data.frame(gCentroid(iran, byid = TRUE))
centers$state <- dat$state


### This is hrbrmstr's own function
theme_map <- function (base_size = 12, base_family = "") {
theme_gray(base_size = base_size, base_family = base_family) %+replace% 
theme(
axis.line=element_blank(),
axis.text.x=element_blank(),
axis.text.y=element_blank(),
axis.ticks=element_blank(),
axis.ticks.length=unit(0.3, "lines"),
axis.ticks.margin=unit(0.5, "lines"),
axis.title.x=element_blank(),
axis.title.y=element_blank(),
legend.background=element_rect(fill="white", colour=NA),
legend.key=element_rect(colour="white"),
legend.key.size=unit(1.5, "lines"),
legend.position="right",
legend.text=element_text(size=rel(1.2)),
legend.title=element_text(size=rel(1.4), face="bold", hjust=0),
panel.background=element_blank(),
panel.border=element_blank(),
panel.grid.major=element_blank(),
panel.grid.minor=element_blank(),
panel.margin=unit(0, "lines"),
plot.background=element_blank(),
plot.margin=unit(c(1, 1, 0.5, 0.5), "lines"),
plot.title=element_text(size=rel(1.8), face="bold", hjust=0.5),
strip.background=element_rect(fill="grey90", colour="grey50"),
strip.text.x=element_text(size=rel(0.8)),
strip.text.y=element_text(size=rel(0.8), angle=-90) 
)   
}

ggplot() +
geom_map(data = map_df, map = map_df,
         aes(map_id = id, x = long, y = lat, group = group),
         color = "#ffffff", fill = "#bbbbbb", size = 0.25) +
geom_text(data = centers, aes(label = state, x = x, y = y), size = 3) +
coord_map() +
labs(x = "", y = "", title = "Iran Province") +
theme_map()

Diondione

It seems that GADM's data are not trustworthy! – Dickie

How to change color for specific province? – Prank

Could you see #69970729 ? – Prank