title: Is there a way to make nice "flow maps" or "line area" graphs in R?
body: <p>I'm trying to find a way to recreate graphs like these directly in R (as opposed to manually drawing them with Inkscape after I've done the analysis in R):</p>
  
  <p><img src="https://i.stack.imgur.com/9gCV0.png" alt="line flow 1">   and   <img src="https://i.stack.imgur.com/OlRum.png" alt="line flow 2"> </p>
  
  <p>The first one seems like it should be straight forward, but I'm not able to find anything that fits my needs... the second one is much more complicated, but also seems like it <em>should</em> be doable.</p>
  
  <p>This post <a href="https://stackoverflow.com/questions/16112162/graph-flow-chart-of-transition-from-states">Graph flow chart of transition from states</a> gets me about as close (it's kind of awesome already, except I don't necessarily have a square matrix, and I'd like to designate a start/end location for my lines with control over thickness and alpha based on my own data)...</p>
  
  <p>Is it possible to do this using ggplot (or maybe something else like lattice, if it looks nice)? </p>