Maps
Geographic data is often best visualized on a map - whether it's a simple thematic map or a slippy map with loads of details.
Thematic maps
A thematic map focuses on some specific theme, often to illustrate data. As such, thematic maps are often very simple so that unnecessary details don't obscure the objective.
The map below, for example, shades North Carolina's Congressional districts by projected Democratic vote share vs Republican vote share. You can hover over or touch a district to find that Democratic vote share.
The "estimated vote share" is determined by the results of all three of the statewide elections from 2020. An important point to note is that, of the votes cast for Democrats or Republicans in that election, 50.3% were for Democrats and 49.7% were for Republicans. Thus, it might be reasonable to hope that the representation in Congress would be very close to 50/50. The table below shows otherwise, which strongly suggests partisan gerrymandering.
| Strongly Republican | Leaning Republican | Leaning Democratic | Strongly Democratic |
|---|---|---|---|
| 10 | 0 | 1 | 3 |
Slippy maps
Slippy map is the colloquial term for a tiled web map - i.e. an interactive map that allows you to pan and zoom to see a high level of detail. Popularized by Google Maps, slippy maps are often used for navigation. They can also be used to illustrate data, which is particularly appropriate when fine details are important.
The map below illustrates the 50 districts for the North Carolina state senate races this Fall of 2024. You can click on a district to find the candidates. You can also zoom in to view the district lines very precisely - for example, to find in which particular district you might happen to live.
Activity maps
The first two maps are built entirely on top of free, open source tools. As awesome as those tools are, the most detailed slippy maps and best tools to access them are built by Mapbox, the only commercial product I use with any regularity.
If you want to build a map that displays outdoor activities, for example, then it's hard to beat Mapbox's outdoor maps. The map below uses Mapbox to display a few of the bike rides I've done around the country in recent years.
You can use the drop down menu to zoom in to a particular ride and then pan/zoom to explore to your heart's content. An interactive elevation chart should also appear that connects with position on the map.