Tobler's second law of geography
One of several proposed laws of geography / From Wikipedia, the free encyclopedia
The second law of geography, according to Waldo Tobler, is "the phenomenon external to a geographic area of interest affects what goes on inside."[1][2][3][4] This is an extension of his first. He first published it in 1999 in reply to a paper titled "Linear pycnophylactic reallocation comment on a paper by D. Martin" and then again in response to criticism of his first law of geography titled "On the First Law of Geography: A Reply."[1][2] Much of this criticism was centered on the question of if laws were meaningful in geography or any of the social sciences. In this document, Tobler proposed his second law while recognizing others have proposed other concepts to fill the role of 2nd law. Tobler asserted that this phenomenon is common enough to warrant the title of 2nd law of geography.[2] Unlike Tobler's first law of geography, which is relatively well accepted among geographers, there are a few contenders for the title of the second law of geography.[5] Tobler's second law of geography is less well known but still has profound implications for geography and spatial analysis.[6]
Tobler's second law of geography has implications whenever a boundary is drawn on a map, particularly in arbitrary boundaries such as political borders.