A Researcher Explains Why These Lovely Infographic Maps Can Be So Deceptive

From reporting election outcomes to issuing climate forecasts, maps provide a strong, accessible and visually interesting method to convey advanced data.

However as a researcher specializing in knowledge visualisation, I am conscious that even probably the most stunning maps can introduce a point of misrepresentation.

To see how, take into account the most recent statistics on deprivation launched by the UK authorities. The federal government ranked 32,844 neighbourhoods, based mostly on measures of deprivation corresponding to revenue, employment, well being and crime.

The figures had been broadly reported, from the BBC to The Guardian and the Every day Mail, reigniting long-standing debates about persistent inequality in England.

In fact, many retailers used maps to share these findings with the general public. However utilizing conventional boundaries can divert readers’ consideration away from essential data.

Within the BBC’s map of deprivation throughout native authorities, as an example, sparsely populated rural areas dominate a disproportionately giant space, whereas city areas, corresponding to London, containing hundreds of thousands of individuals, are rendered virtually invisible.

The map included within the BBC’s report on deprivation is fascinating. It could be good to check out the Ofsted ranking of colleges in probably the most disadvantaged areas… https://t.co/iUR2hINBRn pic.twitter.com/lFq6s8l1In

— SailingAway (@Heatherleatt) September 27, 2019

Distorted knowledge

Current analysis reveals that individuals can interpret data inaccurately, after they take a look at maps with these shortcomings. However different methods can be utilized to create a extra correct impression of the underlying knowledge.

As an illustration, cartograms intentionally distort geography by scaling areas in line with a selected variable, corresponding to native inhabitants.

Another approach of visualising the world’s inhabitants. (Max Roser/Our World in Knowledge./CC BY 2.zero)

Dorling cartograms take this one step additional, scaling areas in line with a specified variable, but additionally representing every space utilizing the identical form, corresponding to a sq. or a circle.

Different strategies obtain uniformity in each measurement and form: hexograms and geogrids remodel the unique boundaries of the map into hexagons or squares of the identical measurement, whereas nonetheless aiming to protect their authentic association.

Mapping neighbourhood deprivation in England represents a major problem, even for consultants. It’s because the federal government defines a neighbourhood as a “decrease tremendous output space” – every of which comprises round 1,500 residents.

As a result of extremely disadvantaged neighbourhoods are typically densely populated, they’re much less seen on an everyday map. Against this, wealthier suburban areas – which are sometimes much less densely populated and subsequently a lot bigger – dominate the map.

So there is a danger that readers may draw inaccurate conclusions in regards to the stage of deprivation in any given space.

Shaping up

Utilizing Dorling cartograms scaled by resident inhabitants, and common hexagonal geogrids, I’ve tried to minimise any misrepresentation. Take the instance of Blackpool, which was ranked probably the most disadvantaged native authority in England.

Round 42 p.c of neighbourhoods in Blackpool are within the high 10 p.c most disadvantaged in England (the “first decile”). But these neighbourhoods solely make up round 29 p.c of the town’s precise space.

(Samuel Langton/MMU, utilizing OS Knowledge © Crown copyright 2019)

Utilizing a Dorling cartogram scaled by resident inhabitants measurement, neighbourhoods within the first decile now take up 41 p.c of the map’s space, and the bigger, much less disadvantaged neighbourhoods (in mild blue) have been shrunk accordingly to develop into much less dominant.

With an everyday hexagonal geogrid, the map now mimics the underlying knowledge, with neighbourhoods within the first decile of deprivation taking on 42 p.c of the full space.

The variation within the sizes and shapes of Blackpool’s neighbourhoods can not divert consideration or mislead readers, and arguably, the underlying knowledge has been conveyed extra precisely than with the unique map.

Mapping deprivation in another way

A hanging distinction will be seen utilizing various kinds of maps to visualise deprivation in Burnley and Hartlepool, which had been amongst England’s most disadvantaged native authorities.

Each areas are characterised by many small, densely populated neighbourhoods within the first decile (most disadvantaged), surrounded by a lot bigger and wealthier suburbs.

At first look, deprivation seems understated within the map that makes use of the unique boundaries. However with the Dorling cartogram (once more scaled by inhabitants) and the hexagonal geogrids, the problem will be considerably rectified. This comes with its personal difficulties, although.

The geogrid specifically pushed some neighbourhoods additional aside and compelled some nearer collectively than they seem on the unique map.

This may show problematic in instances the place the first intention of the map is to convey distinct geographic patterns, such because the clustering of extremely disadvantaged neighbourhoods. In making the transformation, these patterns is perhaps misplaced, or spurious patterns generated.

Encouraging experimentation

Birmingham and Manchester – ranked within the high ten most disadvantaged native authorities – current a distinct problem. With a lot bigger populations, and plenty of extra neighbourhoods to visualise, the unique map presents an awesome quantity of knowledge.

As soon as once more, each the Dorling cartogram and the geogrid carry out admirably, cutting down the visible affect of bigger, wealthier areas (particularly within the north of Birmingham) and making the maps simpler to learn – with out skewing the geographic patterning of deprivation throughout every metropolis.

There are not any agency guidelines about how finest to create stunning however correct maps. On this case, utilizing the most recent neighbourhood deprivation knowledge in England, mapping out the unique boundaries can clearly introduce a point of misrepresentation.

There’s actual worth in experimenting with completely different cartographic methods – and media organisations and the federal government would do effectively to assume exterior the field on the subject of sharing the most recent findings with the general public.

Samuel Langton, PhD Candidate in Sociology, Manchester Metropolitan College

This text is republished from The Dialog underneath a Inventive Commons license. Learn the unique article.