Feedback on Size of Circles

[heidekrueger]

Hi Martin,

I came across your map on LinkedIn today, cool project!

Some short feedback on your data vizualisation: You're using the rated power for the size of the cirlces.
However, psychologically we perceive the area of the circle rather than its radius/diameter, and as a result, a battery with 50MW rated power in your map looks 25x as large as one with 10MW (pi x 50x 50 vs pi x 10 x10), and 2500x as large as one with 1MW.

I would suggest that you use sqrt(rated power) for the circle size instead.

I don't want to sound pedantic, but this really does make a big difference. For example, after my first glance at your map I got a lot more worked up about Bavarian politicians than what was fair (at least in this specific instance ;) ). Joking aside, it's hard to relate the power of many small circles to that of one large circle in the current implementation.

Thanks for making and releasing open source projects and making important topics such as this accessible to less technical people!

Cheers
Stefan

[0-k]

Hi Stefan, thanks for the feedback. I thought about this as soon as I posted it and you are correct with the math that the area increases quadratically - I don't quite agree though that we perceive circular areas in a linear way either. I think something in the middle between 0.5 (sqrt) and 1.0 (current implementation) would be most appropriate, even though that might be technically incorrect - I hope to release an update with different scaling versions soon.

Best regards, Martin

[0-k]

https://makingmaps.net/2007/08/28/perceptual-scaling-of-map-symbols/