Mapping is one of the most common forms of data visualisation. Some of these images have small data sets behind them (like the map of writing systems), others have massive amounts (like the map of all the rivers in the contiguous United States).

Average Age of First Sexual Intercourse by Country, ChartsBin.com

Most of these maps make information accessible, and for some, also help contextualize scale.

The thing that is missing in each of these, though perhaps they are listed on their source websites, is information or metadata about the data sources. In today’s digital media and web era where images and text can be easily separated, it is important that the image contains relevant and complete information if it is to be taken seriously, especially when images can be taken out of their original context.

Metadata such as data sources, when the image was created, by whom, and any major assumptions should be part of the image, even in small text if necessary, if the image is to be used in anything more than a meme.

Check out the 40 maps here:

http://twistedsifter.com/2013/08/maps-that-will-help-you-make-sense-of-the-world/