We've touched on geographic visualization throughout the book. You've seen symbol maps and filled maps. Here, we'll examine an example using a custom geocoding technique and custom shapes to give some idea of what is possible.
We saw in Chapter 1, Creating Your First Visualizations and Dashboard, that Tableau generates the Latitude and Longitude fields when the data source contains geographic fields, which Tableau can match with its internal geographic database. Fields such as country, state, zip code, MSA, and congressional district are contained in Tableau's internal geography.
However, if you have latitude and longitude in your dataset or are able to supplement your data source with that data, you can create geographic visualizations with great precision. There are several options for supplying latitude and longitude for use in Tableau:
Include latitude and longitude as fields in your data source. If possible, this option will...