Geographic patterns are spatial patterns that reveal how close different types of populations or phenomena are to one another. They can be actual or perceived patterns related to a specific series of events or occurrences that can be ascribed to a geographic region. Identifying patterns and trends is the second concept of geographic thinking. A pattern is a characteristic or feature that repeats over space: within and between places or regions. For example, low latitudes are warm and wet, while high latitudes are cold and dry. Rivers form distinct and predictable drainage patterns depending on the rock and soil of a region. A trend is when a characteristic or feature changes over time or space.
Geographic patterns can be used to make inferences about population histories and the evolution of inherited disease. Genetic diversity is constrained by factors operating in geographic space. The statistical methods describing genetic variation in space, such as estimation of genetic variances, mapping of allele frequencies, and principal components analysis, have opened up the possibility to reconstruct demographic processes. These studies have significantly contributed to our understanding of human genetic variation.
