title: How to plot longitude-latitude points on a map with different color using ggplot2 package?
body: <p>I have a dataframe contains variable named ID, longitude(LON),latitude(LAT) which you can <a href="https://drive.google.com/file/d/0ByY3OAw62EShTjJQM0NkQXZfUjA/view?usp=sharing" rel="nofollow noreferrer">download from here</a>. I have plotted some longitude-latitude on a country map with same color using <code>ggplot2</code> package with following code:</p>
  <pre><code>library(ggplot2)
  library(raster)
  read.csv(&quot;station.csv&quot;)
  skorea&lt;- getData(&quot;GADM&quot;, country= &quot;KOR&quot;, level=1)
  plot(skorea)
  skorea&lt;- fortify(skorea)
  
  ggplot()+
    geom_map(data= skorea, map= skorea, aes(x=long,y=lat,map_id=id,group=group),
             fill=NA, colour=&quot;black&quot;) +
    geom_point(data=station, aes(x=LON, y=LAT), 
               colour= &quot;red&quot;, alpha=1,na.rm=T) +
    scale_size(range=c(2,7))+
    labs(title= &quot;coordinate data of seoul&quot;,
         x=&quot;Longitude&quot;, y= &quot;Latitude&quot;)+
    theme(title= element_text(hjust = 0.5,vjust = 1,face= c(&quot;bold&quot;)))
  </code></pre>
  <p>And I got the following plot
  <a href="https://i.stack.imgur.com/biR2e.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/biR2e.png" alt="enter image description here" /></a></p>
  <p>Now I want some of those point will be plotted on map with different color according to their ID. For example, I want these ID (111141,111142,111241,111281,111301,131141,131144,131161) will be with blue color and rest of ID will remain with red color. How can I do this?</p>