Cartogram: Reshape Your Map to Tell the Truth

• Activity Number: 465
• Type: Contributed
• Date/Time: Wednesday, August 6, 2014 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistical Graphics
• Author(s): Xiaoyue Cheng*+
• Companies: Iowa State University
• Keywords: cartogram ; choropleth map ; R language

Abstract

People often use choropleth maps to visualize geographic and spatial data. However, those maps usually attract people's attention on the large regions, and make people ignore the small but crucial areas. Cartogram provides a way to solve this problem. Cartogram is an area map with a thematic variable substituted for land area or distance, hence the important areas are emphasized by increasing the size and reshaping the border. Among tens of cartogram variations, the main difficulty is the trade-off between preserving the shape and making the accurate area corresponding to the thematic variable.

In this talk I will introduce an R package cartogram, which creates different types of cartograms, including Dorling and Dorling-like cartograms, non-contiguous and grid-based contiguous cartograms. Compared to the other package Rcartogram, which provides diffusion-based cartogram, the new package is more flexible and easier to use with a graphical user interface.