Distance decay describes the concept of diminishing distance as one gets closer to the destination point. A true direction is measured in angular degrees. Studies of very small regions are often referred to as microscale studies. If clustered point locations are dispersed in space they often follow random distribution. Functional association refers to the fact that some spatial phenomena may attract other phenomena that are in some ways complimentary in nature.
Region is area surrounded with administrational boundaries.
Discrete geographic phenomena are those that have confidentiality limitations. Continuous geographic phenomena are those that last a long time. Long time in geography is defined by the duration of continuous geographic phenomena. Derived variables can be collected directly from ground surveys. Mean of a variable is the value where half of the observations are smaller than this value and half are greater.