title: How to add points into map?
body: <p>There is the first part of the question: <a href="https://stackoverflow.com/questions/29233480/how-to-join-two-maps-into-one-in-r">How to join two maps into one in r?</a></p>
  
  <p>Complete code to bind two maps SWE and NOR (shp data were downloaded from: <a href="http://www.gadm.org/country" rel="nofollow noreferrer">http://www.gadm.org/country</a>):</p>
  
  <pre><code>library(maptools)
  
  mapa_shp_swe &lt;- readShapePoly("C:/r/SWE_adm/SWE_adm0.shp")
  mapa_map_swe &lt;- fortify(mapa_shp_swe)
  
  swe &lt;- ggplot(mapa_map_swe, aes(x = long, y = lat, group=group)) + 
    geom_path(size=1) +
    theme_bw()
  
  mapa_shp_nor &lt;- readShapePoly("C:/r/NOR_adm/NOR_adm0.shp")
  mapa_map_nor &lt;- fortify(mapa_shp_nor)
  
  nor &lt;- ggplot(mapa_map_nor, aes(x = long, y = lat, group=group)) + 
    geom_path(size=1) +
    theme_bw()
  
  n &lt;- length(slot(mapa_shp_swe, "polygons"))
  newShape &lt;- spChFIDs(mapa_shp_nor, as.character(n))
  
  newShape2 &lt;- spRbind(newShape, mapa_shp_swe)
  
  map &lt;- ggplot(newShape2, aes(x = long, y = lat, group=group)) + 
    geom_path(size=1) +
    theme_bw()
  </code></pre>
  
  <p>How to add cities (as points) to this map?
  This doesn't work:</p>
  
  <pre><code>cities &lt;- data.frame(ID = c("stockholm","Oslo"),
                       x = c(59.32, 59.95),
                       y = c(18.06, 10.75))
  
  ggplot(newShape2, aes(x = long, y = lat, group=group)) + 
    geom_path(size=1) +
    geom_point(data = cities, aes(x = x, y = y)) +
    theme_bw()
  </code></pre>