Hi guys, 

I'm trying to get started with the PR2 and moving the base
around, using the pr2_2dnav_slam package. I'm running SLAM and I've
subscribed to the map topic which gives messages of the form OccupancyGrid,
but I can't figure out what format the data is in, or specifically how it's
indexed. How do I index the array to get at a specific point? Or is there a
better way to get at a map of the world around the PR2? Thanks, 

-Ibrahim
Awwal