Reference
Choropleth layers — reading the colour shading
A choropleth is a map where the colour of each region tells you the value of one variable. The map ships with several. Flicking between them is the fastest way to view the same territory through three different questions in a row.
Where to find it
On desktop the layer switcher sits in the top-right of the map. On mobile it lives in the same bottom toolbar as the other controls — tap Layers and pick one. Selecting a layer changes the shading immediately; the legend on the side updates to match.
How it works
There are 5 shadings to choose from today. Each one paints every location on the map with one of 7 colour bins. The bins are quantiles: locations get sorted by the metric and split into equal-sized buckets. So the colour tells you the rank, not the raw value.
The layers
- Annual mean temperature — warmer locations darker.
- January temperature — the same shading but for the coldest month. Often more revealing than the annual mean.
- Snow days per year — locations with snow darker.
- Internet download speed — faster locations darker. Source is the latest publicly available Ookla-style aggregate per region.
- Distance to hospital — closer to a hospital is darker. Reversed on purpose; the metric you care about is short distance.
Reading the legend
The legend at the side shows the seven bins and their boundary values. Hovering a bin highlights every location in that bin on the map; clicking pins the highlight. Useful when you are scanning visually and notice a band you want to isolate.
What to keep in mind
Quantile shading is honest about relative rank, but it flattens absolute differences. A country where every location has fast internet still has a darkest bin and a lightest bin. The contrast looks the same as in a country with terrible internet. Read the legend numbers, not just the colours.
Choropleth shading respects active filters: locations that fail the filter are dimmed before the shading is applied. If you have filtered hard, the map can look almost monochrome — that is filtering, not a bug.
Frequently asked
Why does the colour ramp look different in two countries?
Bins are computed per country, so the boundary values are different. The same shade is not the same value across countries — read the legend, not the colour.
Can I overlay two layers at once?
No. Only one choropleth is active at a time. To compare two metrics, switch layers back and forth or open two locations in the details panel and read both numbers there.
Why do some locations look uncoloured?
Either the metric is missing for that location, or an active filter dimmed it below visibility. Open the details panel for one of them — the metric block will say "no data" if the source is missing.
Can I add my own layer based on a CSV?
Not at the moment. The layer set is fixed and tied to ingested data. If you want a custom view of your own data, drop the values into the bulk import dialog as pins with metadata — the pin colour is configurable per import.
Verified · 2026-05-26