OurBlueDot

Atlas reference

How to read the atlas

Insights explain behaviour that is shared across layers: missing countries, ranks, and data-nature labels. They are reference notes for the map, not a blog, not news, and not a stream of opinion.

Each page answers one atlas question, then points back to methodology, sources, theme hubs, and the layers that demonstrate the rule.

Atlas concepts

How the map treats missing countries, coverage gaps, and the UN member set.

Why do some countries appear grey on the map?

A grey country means this atlas does not currently have a finite, comparable value for that country on the selected layer and period. Grey is the missing-data colour. It is not zero, not a score, and not a verdict on the country.

Data interpretation

How ranks, samples, and comparisons are computed from loaded observations.

What does a rank mean?

A rank on OurBlueDot is a comparable-sample competition rank: it orders countries that have a finite value for the same layer and period. Missing countries are unranked. Rank 1 is the highest value in that sample on current layers, not a claim of absolute truth and not a ranking of every country.

Methodology

How each value is classified, and what those labels do and do not mean.

What observed, estimated, calculated, derived, and modelled mean

Every production layer carries a data-nature label: observed, modelled, calculated, or derived. Estimated is not a fifth layer nature. On derived layers such as Estimated Literacy Rate, each country value is tagged reported or estimated. The labels describe how the figure was produced, not how complete or how “good” a country is.