Spreizweite

Spreizweite is a term used in dispersion analysis to describe the typical lateral extent of a spatial phenomenon within a defined area. It refers to the width of the distribution along its primary axis of variability and is used to compare how widely a feature spreads in different contexts.

Etymology and origin: The term derives from Germanic roots, spreizen meaning to spread, and breite meaning width. It has been adopted in multiple disciplines since the late 20th century.

Definition and calculation: The exact definition varies by field, but common practice defines Spreizweite as the distance between the 10th and 90th percentile of projected coordinates along the first principal component, or as the range between the minimum and maximum of the central distribution after dropping outliers. Tools such as principal component analysis, kernel density estimation, or percentile-based methods are used to compute it.

Applications: Ecology (seed dispersal, animal movement), epidemiology (spatial spread of outbreaks), urban planning (spatial extent of suburban expansion). It helps quantify changes over time or compare regions and can be used in conjunction with other dispersion metrics to characterize spatial patterns.

Limitations: The measure is sensitive to sampling density, boundary effects, and the choice of projection or axis. It should be reported alongside methodological details and complemented with additional statistics to provide a fuller picture of spatial variability.

See also: Dispersion; Range; Spatial extent; Variance; Principal component analysis.