From a question to a usable result

Read a map and local indicator

Connect legend, scale, date, territory and method without treating a colour as an individual measurement.

Published 1 October 2026Illustrative examples

Editorial responsibility : Alexis R.

Prepare the task

A map or index describes a territory through a method. A precise-looking display may still have limits in date, coverage and resolution.

1
Identify layers
Record background map, layer and producer. Check whether the data is an observation, forecast or administrative description.
2
Read the reference points
Inspect legend, unit, scale and date. Do not treat colours from different methods as equivalent measurements.
3
State the scope
Explain what the indicator says about the area and what it cannot measure for a person or exact point. Keep documentation with the map.

An example to adapt

Two maps show different colours on the same day: compare pollutant, period, method and area before calling them contradictory.

The directory records identify publishers and link to their official services. Choose by task; inclusion does not guarantee an outcome.

Task, resource and verification
Task	Resource	Check
Explore a background or layer	Cartes.gouv.fr (ancien Géoportail)	Read date, producer and scale.
Understand an air-quality index	Atmo France	Read territory, period and method.
Explore environmental data	Copernicus	Check product, resolution and documentation.

Use these fields in your own notes. This page does not collect your documents or personal details.

UTF-8 CSV, semicolon-separated columns. No sign-up.

Before drawing a conclusion

Do not use a territorial index as a guaranteed measure of individual exposure; read the competent source’s instructions.

Can I average colours?

Read the indicator method; colours are categories, not arbitrary numerical measurements.

Is a detailed map recent?

Visual detail does not establish the data’s date or period.