According to the values and quantities that we want to display, we can choose from various visualizations that can best represent the data. Usually, we choose between line charts, bar charts, area charts (normal or stacked), pie charts, scatter plots, and so on.
It is easy to understand that the same is true for cartographic visualizations. Besides choosing the type of projection that can represent our data properly, we can also choose between the different types of visualization. This section gives an overview of the most common types of cartographic visualization.
Okay, I have talked enough about the theory—let's draw some maps!
Our first map will be a simple symbol map as the one in the following figure. We want to display all earthquakes from the US recorded during the last 30 days; the dataset is taken from http://earthquake.usgs.gov/:
A simple Symbol map
As we can see in the preceding figure, we want to display differently sized and colored points...