Immigration is so often something viewed through a particular lens. A highly charged political issue in many countries, it is emotive, controversial and yet hard to visualize beyond national figures and very local experience.

Both these approaches lack the nuance necessary to understand the reality of immigration. But when the data is plotted onto maps, it becomes possible to see much more clearly.

Kyle Walker is a Professor of Geography at Texas Christian University who decided to take official census data for US cities and plot them onto a map, calling it Mapping Immigrant America.

His work shows where immigrants come from and where they live, and gives a fascinating picture into the melting pots that are US cities.

The maps

Each dot on the map represents 20 immigrants, and each region or origin is represented by a different colour. For instance, Mexican immigrants are represented by red dots, Europeans by orange dots and so on.

Image: Kyle Walker

The maps show clusters of nationalities living in a particular area, like this one of Chicago.

It shows European immigrants living mainly to the north or north west of the city. Mexican immigrants are found predominantly towards the south and west and a cluster of South Asians (light blue) can be seen to the north, as well as further out to the west.

Immigrants from East and South East Asia (green) can be seen in a pocket at the southern end of the city.

Image: Kyle Walker

Walker, who also created a map of educational attainment in America, told the World Economic Forum that he was inspired by the Racial Dot Map created by Dustin A. Cable at the University of Virginia. “I’d long thought a similar map of US immigrants would be of interest, and Mapbox’s technology evolved to the point that this became feasible,” he said. “I originally designed the map for a talk I gave on using data visualization to explore trends in US immigration.”

Take a look at immigration in some other American cities below.

America’s cities

New York

A map of New York City shows that Manhattan island is dominated by those of European and Oceanic origin, as well as Latin American and East and South East Asian origin, with a cluster of sub-Saharan immigrants to the north.

Image: Kyle Walker

Miami

Miami is dominated by blue dots, representing Latin American immigrants.

Image: Kyle Walker

Washington

Washington is more varied, with a strip of European immigrants in the middle, South Asian to the west and south, and sub-Saharan Africa to the north and east of the city.

Image: Kyle Walker

Houston

Houston is much redder, representing a large Mexican population, as well as a mix of Europeans, south, central and south east Asian populations.

Image: Kyle Walker

Walker used demographic data from the 2009-2013 American Community Survey and geographic and demographic Census data from the National Historical Geographic Information System.

“Primarily, I see the map as a tool for individuals to learn something about their communities. I’m an advocate of using visualization to make open datasets more accessible to the public, and I think these types of maps are effective at doing so,” Walker says.

One example he gave to Boston.com was Brockton, a suburb of Boston, Massachusetts, where a cluster of purple dots show the sub-Saharan African immigrant population.

Image: Kyle Walker

“That’s something the map can inform and reveal. It’s something I wasn’t familiar with beforehand,’’ Walker said. “That’s the real power of data visualization.’’