In this chapter, we explained the core elements of D3 (enter(), update, and exit()).
We understood the power of joining data to our visualization. Not only can data come from many different sources, but it is possible to have the visualization automatically updated as well.
Many detailed examples can be found in the D3 Gallery at: https://github.com/mbostock/d3/wiki/Gallery.
In the next chapter, we will combine all of these techniques to build our first map from scratch. Get ready!