title: Map-Navigation Project, How is road data generally stored/represented?
body: <p>Navigation systems like the Garmin and TomTom have always fascinated me.  I've wanted to implement small map/navigation applications to try out various pathing algorithms and expand on my knowledge of them.</p>
  
  <p>This is a two part question:</p>
  
  <p><strong>1.) How is Map data stored?</strong>  - When you have a network of roads, how is this data generally stored?  What parts of the data are retained inorder to reproduce a map later?  Is each road stored as a series of points where it changes direction? What kind of file formats is this data stored in? Are there publically available libraries for easily parsing these files? Does anyone have specifics on how map/road data is stored/represented it would be very helpful.</p>
  
  <p><strong>2.) Navigation/Pathing</strong> - When doing basic pathing on this map data (a la Garmin) is my assumption correct that it is converted to a directed graph?  Is each road intersection a vertex with the edge weights the distance between vertexes?  This is what I was thinking about doing so I could try some basic well known pathing algorithms and see what I get.</p>
  
  <p>I've seen <a href="http://www.bts.gov/publications/north_american_transportation_atlas_data/" rel="noreferrer">this</a> publically available map data on the US but I'm not sure how it is represented and if it is detailed enough for me to be able to build my directed graph out of it.</p>
  
  <p>If anyone has any information I would appreciate it. The more detailed knowledge you have the better.</p>