Collective Mapping and Knowing Which Way to Run the Bases

I've taken a recent liking to OpenStreetMap.  OpenStreetMap, known often simply as OSM, is the wikipedia of mapping -- essentially, an exercise in collective mapping.  OSM is a worldwide, user-created map that can be edited by anyone.  It is then rendered by various different mapping engines, such as Mapnik, which is my current favorite.  The results can be viewed from openstreetmap.org or imported easily into various GIS software such as ArcMap, and used for many types of personal products.  The information is public domain, so there's no concerns about having to worry about map copyrights of a background Google or Bing or Yahoo map when making you're creating your own maps.

Since the information is user-driven, the level of information varies from place to place.  Many areas have decent levels of input, but some parts of the developing world need serious additions.    This is a Mapnik rendering of the area around the Cathédrale Notre Dame in Paris.

[Click on any map for larger, full-sized image.]
 

Central Paris

 Many roads, natural boundaries, and other features are imported from government data, including much of the US Census Tiger shapefiles.  However, much of the additional editing is done by users. 

If you have a large scale color plotter -- or even if you can print out several 8 1/2 x 11 sheets -- I find that OpenStreetMap is especially good as a physically-in-your-hands highway map.  Not only are the highways clearly labeled, but they're color coded by type of highway using standardized Tiger Census Feature Class Codes (CFCCs) so that you can tell whether that US-shielded highway is a divided, limited-access highway, an expressway with access to local roads at-grade, or a backwoods two-lane barely-paved road where you'll decelerate to 25 mph for every small town.   (Since this is a wiki project there's always a chance that something may be vandalized, but it's not like you can add an interstate highway without someone noticing.)

Highways around Upper Sandusky, Ohio.

 As you can see from the above maps, there are extensive tags that have been approved, far beyond the highways, streets, and natural and political boundaries.  There are amenities such as scenic viewpoints, museums, public restrooms, walking paths, ferries, military facilities, conservation areas...  the list goes on and on.

Natural areas around Jenny Lake, Grand Teton National Park, Wyoming

Most importantly, collective mapping can provide valuable pieces of information.  One of my favorite user edits is Fenway Park.  Now there's no excuse if you've just hit a line drive up the middle and you have no idea which way you should go.

Fenway Park.  Note the one-way arrows on the footpath marking the bases. 

I highly recommend playing around with OSM.  Drawing buildings is soothing in its own special way.  The tools are easy to use, and there are beginners guides for those just starting out and helpful hints on best pratices.   Before you know it, you'll have added detail to half your hometown.