Compare reference websites by purpose and evidence

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First decide what you need: a primary document, an explanation, a dataset or a service. Two resources on the same subject can serve different purposes. Start with a subject to narrow the choice, then select two or three records.

Resource 1

Resource 2

Resource 3 (optional)

Compare the documented information

Missing information remains unspecified. Review dates belong to the original records; displaying this table does not recheck the resources.

Selected resources: purpose, evidence and destinations
Criterion	Cartes.gouv.fr (ancien Géoportail)	Atmo France	Copernicus
Purpose	The public mapping service succeeding Géoportail, with maps, aerial imagery and geographic data for the French territory.	France’s federation of approved air quality monitoring associations, with ATMO index documentation and access to regional information.	European Earth observation programme, with access to environmental services and data.
Publisher	Institut national de l’information géographique et forestière	Atmo France	Union européenne
Origin	France	France	Europe
Subject	Travel & mobility	Science & environment	Science & environment
Documented facts and added evidence	Purpose : Maps, aerial imagery and geographic data for the French territory. Metadata to read : Producer, acquisition or survey date, scale and displayed layer. Limit : Zoom and screenshots establish neither measurement precision nor property rights. Sharing and personal objects : Layers and producers can be found in the catalogue. Sharing annotations or imported data requires signing in and saving the objects.	Index pollutants : Ozone, nitrogen dioxide, sulphur dioxide, PM10 and PM2.5. Summary rule : The most unfavourable pollutant category determines the daily index. Limit : Background air quality describes neither every street, indoor air nor annual trends. ATMO index scale : The index is calculated daily at municipal or intermunicipal level. Source: Atmo France — Understanding the ATMO index · consulted on 2026-10-10 Pollen outside ATMO : The ATMO index does not represent pollen or every present pollutant. Source: Atmo France — Understanding the ATMO index · consulted on 2026-10-10	Product : Identify the service, sensor or product used. Time : Compare represented dates and periods. Method : Read resolution, units and quality indicators. Cloud-cover filter : The Browser can limit cloud coverage during search or visualization. Source: Copernicus Data Space — Browser documentation · consulted on 2026-10-10 Displayed composition : Different band combinations or indices change the visualization. Source: Copernicus Data Space — Browser documentation · consulted on 2026-10-10
Initial profile sources	IGN — Cartes.gouv.fr Cartes.gouv.fr — Aide	Atmo France — Indice ATMO	Comparer des observations de la Terre comparables / Compare comparable Earth observations
Documentation consulted	2026-10-09	2026-10-01 Added details: 2026-10-10	2026-10-03 Added details: 2026-10-10
Official destination	cartes.gouv.fr ↗	atmo-france.org ↗	copernicus.eu ↗
Reading exercise and documented fields	No additional reading exercise for this record.	No additional reading exercise for this record.	No additional reading exercise for this record.

Turn the comparison into a useful choice

Read the purpose: choose the resource that supplies the missing document or action.
Check the publisher and source: an explanatory page does not replace an original dataset or formal procedure.
Open the record, then consult the destination for current conditions and applicable dates.
Record the evidence supporting your choice and the uncertainty that remains.

Different review dates do not prove that one website is better. The table does not measure service availability, accessibility, privacy, prices or reliability and does not rank the resources.

· Read the data provenance