Glossary

Data center · Data center (centre de données)

A building, or a floor of one, that houses the computers (servers) which store data and run online services: websites, video, payments, AI. The machines draw a lot of electricity and give it back as heat, which has to be removed. That is why where a data center stands matters for the power grid, for water and for the neighbours.

Network point of presence · POP · Point de présence (POP)

A site where telecom networks keep equipment to connect to each other and to customers, often a room in someone else's building. It is much smaller than a data center. The atlas tracks these sites but counts them apart from data centers, and leaves them out of the indices.

Facility · Site

Any site in the inventory: a data center, a network point of presence, or a site whose kind could not be established (unclassified).

Hub · Pôle

A town and its close neighbours counted as one place. Towns of the same country less than 25 km apart are merged, and a hub gets its own page from 5 facilities.

Operator · Opérateur

The company that runs a facility. A subsidiary trading under its own brand has its own page; its owner is shown when a source establishes it.

IT load · MW · Puissance IT (MW)

The electrical power available to the computers of a data center, in megawatts (MW). 1 MW is a million watts; 1 GW (gigawatt) is 1,000 MW. The atlas shows it only where the operator or another citable source states it, which is the case for a small share of sites.

Power usage effectiveness · PUE

All the electricity a data center draws, divided by the part that reaches its computers. 1.0 would mean nothing is spent on cooling or losses; 1.5 means half as much again. Shown only where disclosed.

Record quality · DQS · Qualité de la fiche (DQS)

Data Quality Score: how complete and well sourced a record of the atlas is, as a grade from A (complete, several sources) to D (sparse) and a score out of 100. It rates the record, not the facility.

Networks present · Réseaux présents

The number of telecom networks recorded as present at a facility. For a town or a country it is the sum over its facilities, so a network present at several sites is counted once per site.

Internet exchange · IX · Point d'échange Internet

A place where networks exchange traffic directly with each other.

Index and pressure · Indice et pression

Each index is a score from 0 to 100 made of several pillars. The pressure score is the same index without its pillar based on documented conflicts: it describes the conditions only, which lets the conflicts be used to test it.

Median · Médiane

The middle value: half of the data centers of a country or hub score above it, half below. With fewer than 10 data centers a single site can move it, and the page says so.

“Higher than N % of data centers” · « Plus élevé que N % des data centers »

Where a site stands among all scored data centers. “Higher than 70 %” means 7 data centers in 10 score lower.

Disclosed, announced, measured · Déclaré, annoncé, mesuré

Disclosed: published by the operator or another citable source. Announced: stated by a developer for a project that is not built, never counted as existing capacity. The atlas does not estimate missing figures.

Tier

A resilience class from I to IV as stated by the operator: the higher, the more redundant the power and cooling.

Aqueduct

WRI Aqueduct 4.0, the World Resources Institute's open atlas of water risk by river basin, the main input of the water stress index.

GADM

An open database of administrative boundaries, used to say which region a facility's coordinates fall in.

Building footprint · Emprise au sol

The outline of a facility's building as drawn in OpenStreetMap. A record with a footprint is located to the building; the others are located as a point.

Campus · Campus

Several buildings of the same operator on one site. When the operator publishes one power figure for the whole campus, each building's record carries it with the mark “campus ×N”, and totals count it once.

Provenance · Provenance

Where a value comes from. Every substantive value of a record keeps the link to the source that states it, so it can be opened and checked.

Column by column: data dictionary. How the indices are built: methodology.