One of my sources of information (and a great time-waster) is the reddit The Silphroad. Today they published an analysis on boundaries and causes of electric biomes in Pokemon GO. In order to better understand the analysis, here is some background.
What are S2 Cells?
S2 cells are a very clever way to represent a region or a point on a sphere (e.g. the Earth) into a single number. S2 Cells use Hilbert Curves to approximate any point (or better squares) in a bigger square.
Basically, a Hilbert Curve draws a line that fills every part of a two-dimensional space. The above image was generated by Scratch at MIT. S2 Cells have different levels, the highest level (level 30) maps an area of less than a square centimeter, the lowest level (level 0) determines an area of about 85 million square kilometers.
Pokémon GO uses S2 Cells as follows:
- Captured locations show the location name of the center of the level 10 S2 cell where the Pokémon was captured.
- An older version of the app requested level 15 S2 Cells to determine nearby Pokémon.
What is a spawn point?
Spawn points are areas where Pokémon appear regularly and stay for some time. According to research, most Pokémon stay for 30 or 60 minutes (originally 15 minutes). A Pokémon will appear at the same spawn point at the same minute past the hour.
What is a biome?
A biome determines what Pokémon a spawn point generates. Open Street Map (OSM) features appear to partially determine biomes. Biomes can overlap.
For those who want to spend more time catching Pokémon than reading long articles, here is the summary:
- The range of electric biomes can be confined to level 14 S2 cells. It is possible that all biomes use S2 cells of either the same, or varying levels.
- Electric biome S2 cells form clusters of multiple cells across the map with twists and turns, it is rare for an electric biome to exist in just one level 14 cell.
- The most important features in generating an electric biome are: water, piers and car parking. The biome can exist with one or more missing, they do not need to occur in every cell in a cluster.
- More than one type of biome can overlap in a cell.