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Reuters Graphics newsroom Datawrapper guide

Custom locator maps with shapefiles

Shapefiles are a widely-used file format for storing geographic data and are often the preferred way sources share GIS data with us. They’re also widely available on the web through open data and government access portals.

In this tutorial, we’ll use shapefiles from the Insititute for the Study of War and AEI Critical Threats Project to create an analytical map of the Russian offensive in eastern Ukraine over the summer in 2024.

You will learn

  • How to convert shapefiles into the GeoJSON format Datawrapper requires with Mapshaper
  • Combine multiple shapefile layers to create an analytical map in Datawrapper
  • Style and annotate your map to make it a clear, compelling read

Video

Watch as we make an area of control map for eastern Ukraine and learn how to use shapefiles with Datawrapper.

TLDR

In a rush? Here’s the basic steps to get your shapefile data into a Datawrapper locator map.

  1. Get your shapefile

    Make sure your source is reputable!

  2. Upload to mapshaper.org

    Import all the files included with your shapefile in mapshaper.org. Your geographic data should immediately appear.

  3. Console: Re-project your map

    Click the “Console” button, type the following command into the text prompt that appears and hit ENTER:

    Terminal window
    -proj wgs84

    You’ve just re-projected your data into the WGS84 projection system Datawrapper uses for locator maps.

  4. Simplify

    Get your file size down to something Datawrapper can handle. Click the “Simplify” button and use the slider to reduce the detail in the map down. Slide to the point just before your map starts to visibly deform at the zoom level you expect to display your map in Datawrapper.

  5. Export to GeoJSON

    Click “Export” and choose the GeoJSON option.

  6. Add to your locator map in Datawrapper

    Paste or upload your GeoJSON in the “Import line and area markers” section on the “Add markers” tab in Datawrapper.

  7. Style your new map layer

    Don’t forget to annotate your map layers and make sure your map’s point is clear to your readers.

Quick glossary

A few terms you’ll encounter in this tutorial.

Shapefile

Shapefiles are a widely-used format for storing geographic data. They typically come as a set of files with different extensions working together. For example, a complete shapefile often includes files with extensions like:

  • .shp - contains geometric shapes on a map like points, lines and polygon areas.
  • .dbf - a database file storing attribute data, like names or population figures associated with the shapes.
  • .prj - a file containing information on the projection of the shapefile.

These files combine to represent the location and attributes of geographic features, such as countries, regions or cities, which you can visualize on a map.

Projection

Projections are coordinate systems used to represent the 3D curved surface of the Earth on a 2D flat surface, like a computer screen.

Different projections change how shapes, distances and areas appear. Some projections preserve shapes, while others maintain accurate sizes, but all projections stretch and change the geography in some way to flatten it out.

For Datawrapper, we need our geographic data projected using the WGS84 system, which is a commonly used standard for mapping and global positioning.

If your geographic data isn’t projected in WGS84, you can re-project it using online tools like Mapshaper. This ensures your geographic data appears correctly on your Datawrapper map and lines up with placenames, borders and other layers Datawrapper also includes.