Global

How to Use Maps Effectively in Climate and Environmental Journalism

27 Jun, 2023

Cracked, dry earth overlays a hand holding a globe

Maps are powerful tools for environmental journalists who want to tell compelling stories about the state of the planet and its resources. Maps can help to visualize complex data, reveal spatial patterns and trends, and communicate the geographic context of environmental issues. Keep reading to see some examples of how maps can be used as effective storytelling tools.

While maps can certainly be useful, not all maps are created equal, and choosing the right type of map for your story can make a big difference in how your audience understands and engages with your reporting. This may sound difficult, but you really don’t have to be a data journalist or multimedia specialist to start incorporating meaningful maps into your storytelling.

In this guide, we will outline various types of maps that can be created and explain how to choose what kind of map to use for what purpose. We’ll also touch on interactivity and provide links to useful mapping tools as well as pointers on what you can do to turn good data into a great map.

Types of maps

There are many types of maps that can be used for environmental and climate journalism, but here are some of the most common ones:

Base maps

These are the simplest maps that show the basic geographic features of an area, such as roads, rivers, cities and borders. They can be used as a background layer for other types of maps, or as a standalone map to provide orientation and location information.

For example, the map below from a story published in The Third Pole shows the planned route of the Qosh Tepa Canal, a controversial canal being built by the Taliban in northern Afghanistan to divert water from the Amu Darya River for irrigation. The map is not very interactive or complex, but it serves the purpose of providing context and background for the story, in a region many readers might not be familiar with.

A map of the planned route of the Qosh Tepa Canal. — *The planned route of the Qosh Tepa Canal / Credit: The Third Pole.*

Choropleth maps

These are maps that use different colors or shades to show how a variable (such as population, income, pollution, etc.) varies across different geographic areas (such as countries, states, districts, etc.). They can be used to compare and contrast different regions or to show spatial patterns and trends. For example, the choropleth map below from a story in The Third Pole about countries most at risk of climate change allows for easy assessment of which countries or regions are most severely affected

A map of countries most at risk of climate change. — *A map of countries most at risk of climate change / Credit: The Third Pole.*

Dot maps

These are maps that use dots or symbols to represent individual data points or events on a map. They can be used to show the distribution or density of a phenomenon (such as wildlife sightings, crime incidents, disease outbreaks, etc.) or to highlight specific locations or cases. For example, this story on wildlife tracking, originally published by Mongabay with Earth Journalism Network’s (EJN) support, that shows the locations of illegal wildlife trade seizures in Southeast Asia in 2020. With dot maps, the size of the dot holds no meaning. If you would like the size of a symbol (for example a bubble) to convey meaning according to its size, you should use a bubble map (see below).

A map of locations of illegal wildlife trade seizures in Southeast Asia in 2020. — *A map of locations of illegal wildlife trade seizures in Southeast Asia in 2020 / Credit: Mongabay.*

Heat maps

These are maps that use colors or gradients to show the intensity or frequency of a phenomenon (such as temperature, rainfall, traffic, etc.) on a map. They can be used to show hotspots or clusters of activity or to show changes over time. For example, the heat map below from a story about reforestation originally published by The Conversation shows the concentration of tree cover across the world:

A map showing concentration of tree cover across the world. — *A map showing concentration of tree cover across the world / Credit: Crowther Lab via The Conversation.*

Bubble maps

Also known as proportional symbol maps, these are a type of thematic map that use circles (or "bubbles") of varying sizes to represent data associated with different geographic locations or areas. The size of each bubble corresponds to the quantity of the variable being represented. For example, in a bubble map showing population, a city with a larger population would be represented by a larger bubble than a city with a smaller population.

Bubble maps can be used to represent a wide range of data, from population statistics to economic indicators and environmental data. The visual nature of bubble maps makes them an effective tool for quickly conveying complex information, as readers can easily compare the relative sizes of the bubbles.

The bubble map below from Mekong Eye shows that by 2032, there will be a total of 468 hydropower dams along the Mekong River and its tributaries, with double the capacity of today's. Dam capacity (megawatt) is represented by bubble size.

*A map of hydropower dams along the Mekong River and its tributaries / Credit: Thibi.co via Mekong Eye.*

Flow maps

A flow map represents the movement of objects, goods, people or even information between different areas. These movements are typically represented by lines or arrows that connect different geographic locations. The thickness of the lines or arrows can indicate the volume or magnitude of the movement, and the direction of the arrows indicates the direction of the flow.

Flow maps can be particularly useful in visually communicating complex environmental phenomena, such as tracking pollution, wildlife migration, resource distribution and the spread of diseases. In a One Health context, where the health of the environment, animals and humans is interconnected, flow maps could show the spread of zoonotic diseases from animals to humans, for example.

The flow map example below is from a Mekong Eye story about coffee exports from Vietnam in 2020:

*A map of Vietnam's coffee exports / Credit: Mekong Eye.*

Satellite imagery

Satellite images, or satellite maps, provide a visual representation of Earth's surface as seen from space. They can be considered a type of thematic map that presents spatial variations of a specific theme or themes, such as vegetation, land use, temperature, human-made structures, etc.

It can be very effective to compare two satellite images taken from the same position but at different times, such as the example below (from “The Hidden Environmental Toll of Mining the World’s Sand” published by Yale Environment 360) which shows the impact of sand mining on the waterway connecting China's Poyang Lake and the Yangtze River over time:

Satelite images show the impact of sand mining on the waterway connecting China's Poyang Lake and the Yangtze River — *Satellite images show the impact of sand mining on the waterway connecting China's Poyang Lake and the Yangtze River / Credit: Yale Environment 360.*

Interactive maps

Almost any kind of map can be made more appealing and engaging to a reader by incorporating elements of interaction or interactivity. In online maps, interactivity refers to the ability of the map to respond to user inputs, allowing the user to explore and manipulate the map content. This can include features such as zooming in and out, panning across different geographical areas, clicking on certain elements to get more information, and changing the layers of information displayed on the map.

There is a wide spectrum of the level of interactivity that an online map can offer. The College of Earth and Mineral Sciences at The Pennsylvania State University explains this well:

“Some maps allow only simple interactions such as panning or zooming, or perhaps show additional information about features on mouse hover or click. Others may be developed for expert users, and include the ability to search, filter, and analyze data, as well as the option to upload the user’s own data for exploration and analysis.”

How to choose what kind of map to use

Choosing the right kind of map for an environment or climate story depends on several factors, including the nature of the story, the data available, and the main points that a journalist wants to communicate to the audience. Here are some general guidelines:

Understand the story: What is the main point or points of the story? Is it about a specific location or does it involve a large area or even the entire globe? Is it about change over time or a single point in time? Different types of maps are better suited to different types of stories.
Consider the data: What kind of data is available for the story? Is it quantitative or qualitative? Is it spatially distributed or focused on specific locations? The type of data available can greatly influence the type of map that can be created.
Think about the audience: Who will be reading or viewing the story? What is their level of familiarity with the topic? What kind of visual representation will be most helpful for them? For example, a general audience might benefit from a simple choropleth map showing pollution levels in different areas, while a more specialized audience might prefer a more complex flow map showing the movement of pollutants.
Experiment and revise: Creating a map for a story is often an iterative process. It can be helpful to create several different versions of a map, get feedback from others, and make revisions as needed.
Consider expert help: If a story involves complex data or requires a particularly sophisticated map, it may be worth working with a cartographer, data visualization expert, or geographic information system (GIS) specialist.

Remember, the goal of the map should always be to help the audience understand the story better. If a map confuses or misleads the audience, it's not serving its purpose.

In this regard, it’s also important for journalists to exercise caution to avoid misrepresenting information. For instance, using a large area to represent a small population can create a false impression of prevalence or dominance. To mitigate this, journalists should strive for accuracy in scale and carefully consider the visual weight of mapped elements relative to their actual values or proportions. It is crucial to provide clear legends and explanations, which help the reader understand what the map represents.

What makes for an effective map?

Clear and informative: The map should be able to present complex data in a simple and comprehensible manner. It should provide information that is accurate, relevant and easy to understand. The use of color, scale and other visual cues should be considered to make the data more understandable.
Interactive: The map should allow users to interact with the information presented. As mentioned above, this could include zooming in and out, panning across the area, clicking on elements to gain more information, and perhaps even altering the layers of information displayed on the map. This allows the user to explore the data in a way that suits them and makes the content more engaging.
Localization: The map should allow users to see data on a localized level, not just on a global or regional scale. This allows readers to understand the impact of environmental issues in their own area, making the story more relevant to them.
Time-based: Many environmental issues change over time, so it might be a good idea to allow users to see how situations have evolved. This could be achieved through a time slider or other such mechanisms that show different periods.
Accessibility: The map should be accessible to all users, including those with disabilities. This could mean ensuring that the map is readable for those with color blindness, or providing alternative text descriptions for those who use screen readers.
Credibility: The sources of the data used in the map should be credible and clearly indicated. This helps to build trust with the reader and ensures that the map is a reliable source of information.
Aesthetically pleasing: Lastly, the map should be visually appealing. This doesn't mean it needs to be overly ornate, but it should be clean, well-organized and professional looking.

Ultimately, what makes a good map a great map is not just about what data it presents, but how it presents that data.

Useful mapping tools

There are many mapping tools available online (many of them free or low-cost) that can help journalists create different types of maps for environmental stories. Here are some examples:

Google Earth: This is a free tool that provides access to satellite imagery and 3D representations of the Earth's surface. It allows you to explore different locations, create custom maps and share them with others.
Google Maps: This service provides access to road maps, satellite imagery, street maps and 360° panoramic views of streets (Street View). It also offers route planning for traveling by foot, car, bicycle, or public transportation.
Flourish: Flourish is a data visualization tool that offers a wide range of map templates, including dot maps, bubble maps, choropleth maps and even 3D maps. This versatility makes it a useful tool for telling many types of spatial stories related to environmental issues. One of the standout features of Flourish is its focus on interactivity.
Mapbox: This platform offers tools for designing and implementing custom maps, with capabilities for integrating maps with other data visualizations.
Datawrapper: This tool is widely used in journalism to create mobile-friendly, interactive maps and other data visualizations that can be embedded in web articles.
ArcGIS: This is a geographic information system (GIS) used for creating and using maps, compiling geographic data, analyzing mapped information, sharing and discovering geographic information.
Tableau Public: This is a data visualization software that allows you to create interactive maps and other types of visualizations. It is excellent for creating interactive maps that can be easily shared online.
QGIS: This is a free and open-source GIS software that supports a wide range of data formats and provides a variety of tools for analyzing and visualizing spatial data. You can download it from their website.
Leaflet: This is an open-source JavaScript library for creating interactive maps. It's known for its flexibility and efficiency, working well on both desktop and mobile platforms.