rworldmap package countrylist

Question

Is there a way to obtain the list of countries, regions (?) and continents the rworldmap package supports when I want to join data?

I did some google searches and am just starting off with R.

Thanks.

Answer 1

It seems to me the rworldmap package provides some additional functionality on top of the maps package.

If this is indeed the case, you can do the following:

library(maps)
x <- map("world", plot=FALSE)
str(x)
List of 4
 $ x    : num [1:27121] -130 -130 -132 -132 -132 ...
 $ y    : num [1:27121] 55.9 56.1 56.7 57 57.2 ...
 $ range: num [1:4] -180 190.3 -85.4 83.6
 $ names: chr [1:2284] "Canada" "South Africa" "Denmark" "Great Lakes:Superior, Huron, Michigan" ...
 - attr(*, "class")= chr "map"

This extracts the maps database, and the element names contains the name for each map polygon. These names are in fact a multi-level list where the elements are separated by colons. For example, to get the list of polygons belonging to the UK:

x$names[grep("UK", x$names)]
 [1] "UK:Gibralter"                         
 [2] "UK:Scotland:Isle of Lewis"            
 [3] "UK:Pitcairn Island"                   
 [4] "UK:Guernsey"                          
 [5] "UK:Great Britain"                     
 [6] "UK:Scotland:Shetland Islands:Unst"    
 [7] "UK:Saint Mary's"                      
 [8] "UK:Scotland:Shetland Islands:Yell"    
 [9] "UK:Northern Ireland"                  
[10] "UK:Bermuda"                           
[11] "UK:Tristan da Cunha Island"           
[12] "UK:Scotland:Saint Kilda"              
[13] "UK:Scotland:Ruhm"                     
[14] "UK:Scotland:Benbecula"                
[15] "UK:Scotland:North Uist"               
[16] "UK:Saint Helena Island"               
[17] "UK:Scotland:Island of Skye"           
[18] "UK:Scotland:Barra"                    
[19] "UK:Scotland:Island of Mull"           
[20] "UK:Henderson Island"                  
[21] "UK:Isle of Sheppey"                   
[22] "UK:Jersey"                            
[23] "UK:Scotland:Coll"                     
[24] "UK:Scotland:Jura"                     
[25] "UK:Scotland:Island of Arran"          
[26] "UK:Scotland:Tiree"                    
[27] "UK:Scotland:Islay"                    
[28] "UK:Ascension Island"                  
[29] "UK:Scotland:Colonsay"                 
[30] "UK:Scotland:Shetland Islands:Mainland"
[31] "UK:Scotland:South Uist"               
[32] "UK:Scotland:Orkney Islands:Hoy"       
[33] "UK:Gough Island"                      
[34] "UK:Scotland:Orkney Islands:Mainland"  

Answer 2

Looking at one of the vignettes it appears that this should work:

require(rworldmap)
data(countryExData)
countries <- countryExData[, 2]
EPI_regions <- countryExData[, 3]
GEO_regions <- countryExData[, 4]

If you wanted to get the continental divisions taught in grammar school then there would be further processing needed on the GEO_regions:

> countryExData[ 1:10, 2:4]
                            Country                  EPI_regions
1                            Angola           Sub-Saharan Africa
2                           Albania    Central and Eastern Europ
3  United Arab Emirates             Middle East and North Africa
4                         Argentina    Latin America and Caribbe
5                           Armenia Middle East and North Africa
6                         Australia    East Asia and the Pacific
7                           Austria                       Europe
8                        Azerbaijan    Central and Eastern Europ
9                           Burundi           Sub-Saharan Africa
10                          Belgium                       Europe
             GEO_subregion
1          Southern Africa
2           Central Europe
3        Arabian Peninsula
4            South America
5           Eastern Europe
6  Australia + New Zealand
7           Western Europe
8           Eastern Europe
9           Eastern Africa
10          Western Europe

Answer 3

Take a look at the map_data function in ggplot2. It converts R maps to data.frames.

Answer 4

I'm reasonably sure that the names are not the same as in the maps package. You can get a list of names and codes with this code.

library(rworldmap)
temp_map = getMap(resolution='coarse')
temp_map@data

The names are in temp_map@data[['NAME']]. However, it's a good idea to use one of the ISO code sets if you can. Names are extremely inconsistent between data sets, and sometimes frustrating differences will break it. For example, Cote d'Ivoire can be given with or without the circumflex, and the circumflex is sometimes encoded differently even though it is displayed the same.

Answer 5

I got an error that led me to this solution getMap()$NAME