DigitalArchLand makes videos on YouTube for landscape architects.  He is starting a new series on SketchUp basics.  In this first video he is showing how to import an image of a street plan with lots and how to get it to scale.  Once a base plan like this is at scale, one can add lots of 3D information about the street, the trees, and the building types as well as many more details.

Check out this first video and follow along either on YouTube or as I post those videos here.