In this chapter, you learned all the necessities to draw cartographic visualizations with D3. You learned about the geographic coordinate system, the graticules, and color scales.
GeoJSON is an important format to encode geometric features; it can store different types of geometries and values. However, it also stores a lot of redundant information; that's where TopoJSON comes handy.
Finally, we start drawing different cartographic visualizations, such as symbol maps and Choropleth maps.
In the next chapter, you will learn about testing the responsive visualizations.
