![Javascript 4 U show](https://d3dthqtvwic6y7.cloudfront.net/podcast-covers/000/042/891/small/javascript-4-u.jpg)
Summary: It's easy to add additional layers to a map (subway systems, sewers, etc) - so long as the additional layers exist. Today we'll look at a simple example
Summary: It's easy to add additional layers to a map (subway systems, sewers, etc) - so long as the additional layers exist. Today we'll look at a simple example