Multivariate map

It has potential to reveal relationships between variables more effectively than a side-by-side comparison of the corresponding univariate maps, but also has the danger of Cognitive overload when the symbols and patterns are too complex to easily understand.

[5] Multivariate thematic maps found a resurgence starting in the middle of the 20th Century, coinciding with the scientific turn in geography.

[7] Their often complex patterns of multiple colors has drawn acclaim and criticism ever since,[8] but has also led to research to discover effective design techniques.

[9][10] Starting in the 1980s, computer software, including the Geographic information system (GIS) facilitated the design and production of multivariate maps.

It has also been suggested that in some cases, a map might not be the best tool for studying a particular multivariate dataset, and other analytical methods may be more enlightening, such as cluster analysis.

Bivariate choropleth map comparing the Black (blue) and Hispanic (red) populations in the United States, 2010 census; shades of purple show significant proportions of both groups.
An 1858 multivariate map by Charles Joseph Minard, using a nominal choropleth to represent departments that supplied meat to be consumed in Paris, proportional circles to represent significant volumes of that meat, combined with pie charts dividing it into relative proportions of beef (black), veal (red), and mutton (green).
A multi-layered thematic map, displaying minority proportion as a choropleth, and family size as a proportional symbol
A multivariate symbol map of the 2016 U.S. presidential election, using a combination proportional and chart symbol
A bivariate dot density map showing the distribution of the African American (blue) and Latino (red) populations in the contiguous United States in 2010.