So, that was summer then…
As I walked to work this morning and got drenched in the rain for the umpteenth time this season I checked my phone to see another ‘Amber warning’ from my Met Office App.
It did get me thinking about the recent events in the Caribbean and Florida and thankful that I wasn’t having to leave my home or be holed up in a bunker with Richard Branson.
The satellite images of any storm across the Atlantic are fascinating and equally terrifying. That fear comes from our knowledge of storms and also how they are represented.
The image below shows a swirling mass of colour over a calm sea of greys. It looks scary. As viewers we are educated to understand that the strongest part of the storm is indicated by red. But why do we use these colours? Who chose this system to represent storms? The red and yellow contrasts so strongly against the other colours that more importance is placed on this area. Visually it looks so much stronger than any other part of storm.
As a designer I am attuned to using colour to emphasis information, educate the reader or communicate an ascetic response. I started to Google why storms always look like angry rainbows and discovered that rainbow colour scales are a source or ire in the cartographic community and it has its own catchy hashtag #endtherainbow or #endrainbow.
There has been plenty of scientific research in how the human eye perceives colour. Although the non-colour blind amongst us will see a range of colours, we will also notice that some colours look lighter or darker than others due to the different types of cones in our eyes. These different types of cones and how they are positioned means that we’re not that good at detecting changes of colour across a spectrum of colour and will see other colours as more prominent than others. For example, our eyes will see yellow as the most dominant colour.
Understanding how our eyes perceive colour means that when you look at the image of the storm you can see how visually inaccurate the storm image is. If the colours are representing wind-speed does that mean that the yellow and red areas are significantly faster than the green? Are they colder or warmer? This inaccuracy of data using rainbow colours is the reason why scientists and cartographers have been promoting colour scales that use hue, saturation and brightness.
Interestingly, The National Weather Service had to adapt its colour charts to communicate the highest levels of rainfall for Hurricane Harvey
“So much rain has fallen, we’ve had to update the colour charts on our graphics in order to effectively map it,” the National Oceanic and Atmospheric Administration tweeted. A light purple was added to indicate the heaviest area of the storm. Tonally similar to the outer yellows but obviously communicating different information.
This map from the New York Times shows a tonally accurate view of the same event. It communicates the areas of heaviest and lightest rainfall.
In conclusion rainbow graphics may be visually interesting and create a sense of drama, but for accuracy and scientific analysis tonal representation is a fairer representation. It’s always interesting to question why things are the way they are. You can read more here.← Back To Blog