Simple Science

Cutting edge science explained simply

# Mathematics # Computational Geometry # Numerical Analysis # Numerical Analysis

Creating Better Cartograms with New Techniques

Learn how new approaches improve cartograms for visual data representation.

Robert C. Sargent

― 5 min read


Advancing Cartogram Advancing Cartogram Methods reduce distortion in cartograms. New techniques enhance accuracy and
Table of Contents

Cartograms are special maps that change the size of countries or areas based on Data, like population or income. Instead of showing the actual size of places, they reshape them to visually represent information. If you think of it like a game of Tetris, fitting pieces together, that's a bit like what cartograms do-except they sometimes make the pieces look a little weird!

The Challenge

Creating cartograms can sometimes lead to problems. When we change the shapes of places to fit the data, we often end up with Distortions. This means that places can look like they are stretched, squished, or warped out of shape-kind of like a funhouse mirror! So, how can we create cartograms that keep the information intact while not making the shapes look like they belong in a circus?

The Solution: Meshes and Numbers

We came up with a new way to create cartograms by using something called meshes. Imagine a mesh as a web of Triangles that covers the globe. With the help of some smart math and numbers, we can adjust these triangles to minimize how much distortion happens.

The Two Options: On a Flat World or Round World

We have two main ways to work on our cartograms: we can treat the world as flat, like a piece of paper, or round, like a ball. Each way has its pluses and minuses.

Flat and Floppy

In a flat world, we take the globe and squish it down. This is like taking a basketball and making it into a pancake. We place triangles on the flattened version and use our numerical magic to make sure that the areas on the map match our data.

Round and Ready

The round approach is more like playing with a globe. We keep everything in its three-dimensional shape and only change the details as needed. This cuts down on the weirdness that can come with flattening everything out. After we adjust the triangles, we project them back onto our flat maps.

The Best of Both Worlds

We also have a hybrid option, which combines both methods. This is like making a smoothie with fruits from both the flat and round worlds. We optimize the triangles in our round view while keeping in mind how they will look when we finally flatten everything out. The result? Cartograms that keep their shapes while showing the data clearly.

Comparing Methods: A Shape Showdown

To see how our new method stacks up, we compared it to older methods. Some older techniques can make maps look a bit too distorted. For instance, imagine trying to stretch a rubber band to fit a shape. You might succeed, but it can look a bit lumpy!

Rubber Bands and Fluids

Two older methods are the rubber sheet method and the diffusion method. The rubber sheet method stretches and shrinks parts of the map until they fit. The diffusion method imagines the map as a sponge soaking up information, spreading out evenly. While both can create useful maps, they can also introduce a lot of distortion.

Keeping Shapes Intact

With our new approach, we focused on keeping the shapes as accurate as possible. For example, when adjusting smaller islands or countries, we find ways to stretch them perfectly without ruining their shape. No more squished states or floppy islands!

The Tradeoff: Time vs. Accuracy

One downside to our method is that it requires more time to compute than the old methods. While other techniques produce results in minutes, ours might take hours. Think of it like cooking a perfect sauce: it takes time and patience for the best flavor!

How do We Create Our Cartograms?

Let’s break down how we actually create these cartograms step-by-step.

Step 1: Start with a Triangular Mesh

We begin with a triangular mesh covering the globe. Imagine a soccer ball, but instead of a smooth surface, it’s made of tiny triangle pieces.

Step 2: Adjust Vertices

Next, we move the “points” of these triangles (called vertices) to try and get them to match the desired shapes based on our data. This adjustment is where the numerical optimization comes in. We carefully calculate how to shift each point to minimize distortion.

Step 3: Check the Data

Throughout the process, we keep checking to make sure the areas on our map still reflect the data we want to show. It’s like going back and checking your math homework to ensure you got all the answers right!

Final Steps and Cartogram Creation

Once we’ve adjusted the mesh, we create the final cartogram. We project the shapes back to a flat map, ensuring we don’t introduce unwanted distortion.

The Results: Liquid Earth

One of the exciting outcomes of our method is the Liquid Earth projection. This cartogram looks like a beautifully distorted world map but maintains the right area sizes for different regions. If Earth were a liquid, this is how it might look!

Why It Matters

Improving cartogram accuracy matters for many reasons. Better maps can lead to better understanding and communication of important data. Whether it’s population density, economic data, or other factors, a clear visual representation helps everyone from students to policymakers.

The Future of Cartograms

As we move forward, the goal is to further improve these methods. We want to find ways to make them faster and easier to use while still delivering high-quality results. It would be like upgrading from a flip phone to a smartphone-same purpose, but much better!

Conclusion

In wrapping all this up, creating cartograms with a focus on reducing distortion is like learning the best dance moves for a wedding. It takes practice, timing, and a bit of creativity to get it right. With the new mesh and optimization methods, we can create cartograms that are both informative and visually appealing, helping everyone better understand the beautiful world we live in.

Similar Articles