Manitoba population change, 2011 to 2016

Discipline: Demographic and statistical cartography
Tools: ArcGIS
Methods: choropleth mapping, mean centre, quantile classification, inset locator design
Data: Assiniboine Community College

Notes on method

The choropleth is the straightforward half: divisions shaded by percentage change, decline in the north-west, growth in the belt around Winnipeg, a diverging scheme so that the sign of the change is legible before the magnitude.

The mean centre is the half worth explaining. A provincial population mean centre is a single point, and in Manitoba that point is largely an artefact of one city. Plot it for 2011 and 2016 and you learn very little, because Winnipeg dominates both. Plot it twice more with Winnipeg excluded and the four points together say something the choropleth cannot: how much of the province’s apparent centre of gravity is the city, and which direction the rest of the province is drifting independently of it.

Showing all four, rather than picking the flattering pair, is the part I would defend.

Choropleth of southern Manitoba census divisions shaded from red for population loss to blue for growth above 7.8 percent, with growth concentrated in the divisions around Winnipeg and decline across the north-west, plus four mean-centre points in the middle of the map. — Change by census division, 2011 to 2016. Four mean-centre markers sit near division 9: population centre for each year, computed with and without Winnipeg.Base data: ACC. Scale 1:2,250,000Open larger (1669px)