Recommended tools

This page brings together a selection of resources and tools recommended by the Atelier. It follows the main stages of the workflow: from finding inspiration to processing the data, through to finalising the visualisation.

Find inspiration and choose the right representation

Before processing any data or opening software, it is crucial to determine which visual representation best fits the message and the nature of the data. These catalogues, decision trees and inspiration galleries are here to guide you.

Visual Vocabulary Created by the Financial Times, this visualisation classification starts not from the data but from what you want to show: a change over time, a distribution, a correlation or a hierarchy. The catalogue is also available as a poster.
general public
From Data to Viz A decision tree based on the nature of the data (numerical, categorical, temporal, spatial, etc.). The site then guides you towards the most suitable chart formats, while warning about common mistakes to avoid.
general public
Dataviz Index Produced by the agency WeDoData, this catalogue showcases many forms of data visualisation. These often spectacularly designed examples mostly come from news websites.
general public
Data Vis Dispatch A weekly selection of visualisations, maps and charts published in the world’s press, compiled by the Datawrapper team. A good resource for keeping up with current trends in information design.
general public

Working with data

Compute / structure / clean

Google Sheets or other spreadsheets such as LibreOffice Calc or Microsoft Excel. Google Sheets has the advantage of running in a web browser, with a simplified interface and the ability to share or collaborate with others. Unlike Excel, its CSV export is "clean", i.e. directly usable in visualisation applications.
general public
OpenRefine cleans and structures datasets. Despite a rather complex interface, the tool is effective. It benefits from rich documentation maintained by an active user community.
advanced users
Positron uses the R or Python programming language, powerful and especially well suited as it is designed for data. Although it provides an interface to read, manipulate and visualise data, getting started requires a minimum of comfort with code. The user community is large and the documentation is vast.
advanced users
ObservableHQ is a collaborative platform dedicated to data visualisation in the form of an interactive, collaborative notebook. A large community and many examples make it easy to get started.
advanced users

Join (combine two datasets)

A “join” enriches one dataset with another. This operation is common in cartography; it allows you, for example, to add a 3-letter ISO code to a list of countries. For it to succeed, each dataset must share a common column (the one the join is based on).

(Geo) DataMerger Online but secure, it offers a well-designed, educational interface. In particular, it lets you export the result in several formats.
general public

Geocode (assign geographic coordinates to a place)

It is sometimes necessary or useful to have the geographic coordinates of objects in order to map them. Some tools retrieve such information automatically. Among the most common geocoding operations are obtaining latitudes and longitudes from addresses, or the centroids of administrative units.

Beware, though! Before geocoding, it is better to specify the area — for instance by indicating the country in the case of a city (and thus avoid getting Paris, Texas instead of the French capital). After geocoding, always check the result against a map to detect any inconsistencies.

Geocode by Awesome Table is a Google Sheets add-on that obtains geographic coordinates from addresses. This add-on is free. From precise addresses (street, city, region or country) or even place names, the tool assigns longitudes and latitudes in separate columns. The Google Maps database serves as the reference.
general public
Geocoder from the French Base Adresse Nationale. The geocoder on the official adresse.data.gouv site uses the Base Adresse Nationale (BAN) reference. In addition to longitudes and latitudes, geocoding retrieves the other information in the database, including a geolocation accuracy score.
general public

Convert (change a data file’s format or structure)

The standard file format for data-visualisation tools is CSV (Comma Separated Values), which can be opened in a spreadsheet. However, some tools require specific formats or structures — this is notably the case for geographic information. These formats are numerous (Shapefile, GeoJSON, GeoPackage, KML, GPX, etc.), both proprietary and open, and you sometimes need to switch from one to another.

PGC Coordinate Converter The tool converts geographic coordinates from sexagesimal degrees (or degrees-minutes-seconds) into decimal degrees — the latter notation being the one usable by mapping tools.
general public

Extract data

The data you find is not always available in a standard format readable by visualisation tools. You then have to extract it — from a PDF or a website, for example. Unfortunately, mainstream tools for this kind of “scraping” remain few.

Tabula extracts tables from PDFs. The tool avoids manual data entry. Note that it does not work with images (scans in PDF, for example), the result is not always optimal (cleanup is often needed) and, finally, you should always check the output.
general public
Online OCR extracts the text contained in an image using optical character recognition.
general public

Visualising data

Make maps

Khartis is the tool designed by the Atelier de cartographie. It is aimed at newcomers: it is therefore quick to use and easy to discover, thanks in particular to an intuitive interface. Khartis removes the hurdles often found in more expert tools… while offering powerful functions, advice on proven visualisations and fine-grained settings on points that are fundamental in cartography. The documentation provides valuable guidance.
general public
Magrit is a more sophisticated thematic-mapping tool. It draws as much on statistical cartography as on geographic information systems (GIS). Magrit offers many settings while remaining attentive to the proper application of the "rules" of graphic semiology. The tool integrates every step of the mapping process: importing the base map and then the data, joining the two, choosing the map projection, configuring the representations, complete styling and exporting the final image.
advanced users
Mapshaper reads and processes geographic data. Austere in appearance, this tool is nonetheless very effective for viewing the geometry of objects (and their attached data) or for "geoprocessing" (i.e. clipping, merging, aggregating, cleaning or simplifying the objects of a base map) through short, well-documented commands. Among these, base-map generalisation (simplifying outlines) is remarkable.
advanced users
Datawrapper is a mapping tool, accessible and very well designed. Although it offers only the 3 most common map types, the tool stands out for its ergonomic interface, the guidance provided during creation and the quality of its settings.
general public
QGIS is the most widespread open-source geographic information system (GIS) software. It benefits from a vast user community. QGIS is very powerful, but many prerequisites are needed to use it: geographic file formats, projection systems, geoprocessing operations, types of visualisation, etc.
advanced users
Projection Wizard helps you find a map projection suited to a chosen area.
general public
EPSG.io is the official catalogue of map projections for each country or region.
general public

Create a chart / data visualisation

Datawrapper makes charts too! It offers a wide variety of them, finely configurable and even customisable (annotations within charts, titles, sources, captions, etc.). Datawrapper is used by major media outlets, notably because of its interactive-chart capabilities.
general public
RAW Graphs is a data-visualisation tool useful for experimenting with different chart configurations. It offers some chart types that are fairly uncommon or usually produced by those who can code. The tool’s logic is clever: you manipulate visual "dimensions" (hierarchy, size, colour, labels) and assign the dataset’s variables to them.
general public
Chartbuilder is an easy tool for creating charts. By simply copying and pasting data, it offers only bar or line charts, but it is one of the few able to structure charts into series (collections) on a common scale (and avoid stacked bars, which are hard to read).
general public
Observable Plot is a programming language based on the principle of visual variables. It thus allows a wide variety of charts from just a few lines of code. Extensive documentation and many examples help you get started.
advanced users
Gephi is a network-visualisation tool that integrates a wide range of graph-theory algorithms.
advanced users

Choose colours

ColorBrewer offers preset colour palettes for cartography. In addition to the essential parameters, which you can choose, the app shows a map in solid colours to give you an idea of the result.
general public
Chroma.js generates ordered colour palettes (a gradient of shades, then), including diverging ones. The tool interpolates between several colours while keeping a similar gap between each of them.
advanced users
I want hue generates palettes of distinct colours. The tool uses the properties of the HCL colour space (hue, saturation and lightness) to maximise the differences between each colour.
advanced users

Lay out

Edit a visualisation or combine text and image

The raw file exported from visualisation tools often needs to be modified, improved, refined, or even integrated into a document or adapted to a medium.

Adobe Illustrator is professional vector-drawing software. It is needed to edit data visualisations (charts, maps, posters, etc.).
advanced users
Figma is originally an interface-design tool but turns out to be very versatile. It lets you draw freely and edit vector images, including in collaboration with other users.
advanced users
Adobe InDesign is professional layout software. It is useful for combining text and images (reports, posters, atlases, etc.).
advanced users
Affinity is a complete creative suite: vector drawing, photo editing and page layout. It is now entirely free and offers a credible alternative to Adobe Illustrator and InDesign for editing and laying out visualisations.
advanced users