We have spent significant time creating and interacting with maps in our previous chapters. In all our examples, the geographic data was included. In this chapter, we will explain how to find geographic data about any country in the world.
There are typically two sets of data that we will need to create a map in D3:
A dataset that represents the geographic shape of our map (geo data)
Some meaningful data that we want to visualize on the map (for example, population density by US counties or unemployment rate by countries in the world)
This chapter is focused on understanding, manipulating, and optimizing geo data for map visualizations. We will accomplish these goals by:
Explaining three important formats that contain geospatial vector data
Finding, downloading, and working with large amounts of map data
Using techniques to build the right geo data file for your map