A cartogram is a unique type of map that represents data through the distortion of geographical areas, often to reflect a particular variable such as population, economic indicators, or election results. Unlike traditional maps, where geographical accuracy is paramount, cartograms manipulate the size and shape of regions to visually emphasize the data being represented. Here's a guide to understanding and interpreting a cartogram:

1. Understand the Purpose: Recognize that a cartogram is designed to represent data visually, not to provide an accurate geographical representation. The primary goal is to convey information about a variable or set of variables in a spatial context.

2. Identify the Variable: Determine what variable the cartogram is illustrating. This could be population size, GDP, number of internet users, or any other metric. The legend or accompanying text usually indicates this.

3. Recognize Distortion: In a cartogram, the size and shape of geographical areas are altered to represent the variable of interest. For example, in a population cartogram, areas with larger populations will appear bigger than their actual geographical size.

4. Comparing Areas: Look at how different regions are sized relative to each other. This comparison gives you an idea of how the variable being represented varies across regions. For instance, if one country appears much larger on a population cartogram than on a traditional map, it indicates a higher population density.

5. Color Coding: Many cartograms use color coding to represent different levels of the variable. Pay attention to the color scheme (usually explained in the legend) to understand the gradations in the data.

6. Contextual Information: Read any accompanying text or annotations. These often provide context that helps in understanding the reasons behind the distortions and the story the data is telling.

7. Look for Anomalies: Notice any areas that seem disproportionately large or small. These anomalies can indicate interesting or important aspects of the data, such as a small area with a very high population density.

8. Comparative Analysis: If possible, compare the cartogram with a traditional map. This comparison can help in understanding the extent of distortion and the real-world implications of the data.

9. Limitations: Understand that cartograms, while useful for highlighting certain data, can be misleading in other ways. They might oversimplify complex data or create visual biases.

10. Use as a Starting Point: Use the cartogram as a starting point for further inquiry. If a particular distortion or data representation catches your attention, it might be worth investigating more about that region or data point.

In summary, interpreting a cartogram involves understanding what variable it represents, recognizing the intentional distortions of geographical areas to emphasize this variable, and using the visual cues provided (such as size, shape, and color) to understand the underlying data. It's also important to be aware of the limitations of cartograms and to use them as part of a broader analysis rather than as definitive representations of complex data.

Roger Sarkis
Tagged: education