title: How can I plot bounding boxes in ggplot?
body: <p>I have the coordinates for a rectangular bounding box. Example.</p>
  
  <p><code>maxlat = 49,minlat = 30,maxlong = -117,minlong = -125</code> </p>
  
  <p>that defines the bounds.</p>
  
  <p>How can I put a box corresponding to this on the US map?</p>
  
  <p>Basically I am looking for a figure like this:
  <img src="https://i.stack.imgur.com/gAiFk.png" alt="enter image description here"></p>
  
  <p>I want to put six such boxes to put on one US Map. If I can put a serial number like 1,2,3,4 next to the plots, that would be even better. But just putting the boxes there would also be great. </p>
  
  <p>Addendum:</p>
  
  <p>The US Map was made using this:</p>
  
  <pre><code>usamap &lt;- map_data("state")
  ggplot() + 
    geom_polygon( data=usamap, aes(x=long, y=lat,group=group),colour="black", fill="white" )+
    xlab('Longitude')+
    ylab('Latitude')+
    coord_map(projection = "mercator")+
    theme_bw()+
    theme(legend.position = c(.93,.20),panel.grid.major = element_line(colour = "#808080"))+
    ggsave("usmap_blank.png",width=10, height=8,dpi=300)
  </code></pre>