title: shape file, prisecroads, abutting two states
body: <p>Using R, and two shape files: tl_2015_01_prisecroads (alabama) and tl_2015_13_prisecroads georgia), read as two R objects using readOGR(). I need to focus on an area that includes both West Georgia and East Alabama. I tried both rbind() and spRbind() to no avail.</p>
  
  <pre><code>ga_al &lt;- rbind(alabama, georgia, fix.duplicated.IDs=TRUE)
    Error in as(x, "SpatialLines") : 
    no method or default for coercing “logical” to “SpatialLines”
  
  ga_al &lt;- spRbind(alabama, georgia)
    Error in spRbind(as(obj, "SpatialLines"), as(x, "SpatialLines")) : 
    non-unique line IDs
  </code></pre>
  
  <p>Question 1: How to I combine two shape files to map an area in both states?
  Question 2: How would I go about zooming in on a smaller area of the combined shape files?</p>