title: Increase the radius of the Circle in ggplot2
body: <p>I've had trouble increasing the radius of the circle on a map. I've tried the <code>scale_size_continuous</code> with maximum size up to 1000, but the circle size remained the same after all. </p>
  
  <p>My code is in the following:</p>
  
  <pre><code>states &lt;- map_data("state")
  
  gg1 &lt;- ggplot(data=states) +
    geom_polygon(data=states, aes(x=long,y=lat,group=group), 
                 fill = "orange", color = "white") + 
    coord_fixed(ratio = 1.3)+
    geom_circle(data = origCity, aes(x0 = Long, y0 = Lat, r = Percent), 
                fill = "black", color = "black", alpha = 0.5, show.legend = FALSE) +
    scale_size_continuous(range = c(20, 5))+
    theme(panel.grid.major = element_blank(),
          panel.grid.minor = element_blank(), 
          panel.background = element_blank())+
    theme(axis.ticks.x = element_blank(),
          axis.title.x = element_blank(),
          axis.text.x = element_blank())+
    theme(axis.ticks.y = element_blank(),
          axis.title.y = element_blank(),
          axis.text.y = element_blank())
  
  print(gg1)
  </code></pre>
  
  <p>Any suggestions are greatly appreciated!</p>