Atlas concepts

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.

What grey means

The map colours only countries that have a finite numeric value for the selected layer and period. If a record is missing, null, or not a finite number, the country is painted with the layer’s missing-data colour. The legend labels that swatch Missing data. Countries that never received a comparable observation for the loaded period use the same colour.

OurBlueDot maps 193 UN member states. A country outside that registry is not added to fill a source table. Grey on the map is therefore an intended product outcome: incomplete coverage stays visible.

Why a value can be missing

The usual reasons are properties of the source and the join, not a score:

No published observation. The source does not provide a comparable country-period value. Many UN members have no reported rail passenger series on Rail passengers per capita. The EV sales share map follows the IEA sample, not every UN member.
Unavailable for that period. A country can have values in some years and none in others. The atlas does not interpolate the gap, carry the last value forward (unless a layer documents a labelled snapshot carry), or invent a trend.
Reporting and join differences. Rows are joined to UN members by ISO codes or documented name maps. Source aggregates, and territories outside UN-193, are excluded. Some microstates are absent from a given series even when neighbours are present. CO₂ emissions per capita in Monaco is one such gap on the territorial CO₂ layer.

Grey is not zero

A true zero is a comparable observation. It is coloured as a value, ranked among other finite values, and can be indexed like any other country-layer page. Clean cooking access in South Sudan is a published 0 percent estimate, not a grey country. FAO coffee zeros are kept as observations rather than converted to missing.

Clean cooking access in Liechtenstein has no comparable WHO/WDI estimate in the imported series, so the country stays grey on that layer. The country page states that there is no meaningful value; it does not display 0.

Grey is not a negative judgment

Missing coverage is not a ranking, a quality verdict, or evidence that a country “failed to report.” Some gaps are sparse administrative reporting. Some are sample limits in the chosen source. Some are honest absences after refusing to splice a second dataset to complete the map.

Dataset selection prefers source quality, methodological transparency, licensing, and maintainability over maximizing the number of coloured countries. A layer may cover far fewer than 193 members when the source is authoritative. Environment and Mobility maps are especially easy to misread if grey is treated as “fine” or as “worst.” Agricultural water stress that is grey is not “plenty of water.”

This does not measure

Grey does not measure governance, statistical capacity, or importance. It does not mean the true value is small. It does not authorize filling the cell. Country-layer URLs without a finite value stay out of the search index; country profiles still name the gap instead of substituting a number.

Continue in the atlas

These pages are the working examples for this question. They are not a complete catalogue.

Related atlas concepts

Other Insights pages that explain shared atlas behaviour, not a reading list of articles.