Incomplete geographic information is fine

Geographic information is usually incomplete, and that’s okay. People’s minds don’t hold blank spaces very well, so they fill those spaces in with assumptions about how these kinds of landscapes usually work. These assumptions are good enough for them to do the things we need to.

Imperfect data can still result in effective geographic decision making, because of Tobler’s Law (“everything is related to everything else, but near things are more related than distant things”) and because we can generalize from domains we know a lot about to ones we know little about.

In the real world, people don’t need to be able to envision every intersection between here and their house to have a good idea of how to get there. They know how the streets generally work and can make a good enough estimate based on that.

In the digital world, people use available patterns from similar experiences to form these assumptions, which works perfectly as long as designers stick to them. When they’re revealed to be incorrect, people can easily become frustrated or lose trust.


Golledge, Reginald G. “The Nature of Geographic Knowledge.” Annals of the Association of American Geographers, vol. 92, no. 1, 2002, pp. 1–14. Wiley Online Library,