## contour

Overview page. Subjects: Earth Sciences and Geography — Mathematics.

A line on a map joining places of equal heights, and sometimes equal depths, above and below sea level. The contour interval is the vertical change between consecutive contours. Contour...

## cube

Overview page. Subjects: Earth Sciences and Geography — Mathematics.

A hexahedral crystal shape or form which can be referred to three axes of equal length which intersect at right angles.

## Daniel Bernoulli

Overview page. Subjects: Earth Sciences and Geography — Mathematics.

(1700–82)

A Swiss mathematician (one of eleven eminent mathematicians his family produced over four generations), whose most important work was in the field of hydrodynamics. In...

## depression

Overview page. Subjects: Mathematics — Earth Sciences and Geography.

The acute angle between the horizontal and a given line (see inclination) measured positively in the direction of the downwards vertical. θ is the angle of depression of the boat from the...

## dilatation

Overview page. Subjects: Mathematics — Earth Sciences and Geography.

The process in which an applied stress leads to a state of strain involving a change in volume. The change in volume is given by: Δ_{v} = (*V*
_{f} – *V*
_{o})/*V*
_{o},...

## dodecahedron

Overview page. Subjects: Earth Sciences and Geography — Mathematics.

A crystal form composed of twelve rhomb-shaped faces, each face intersecting two of the crystallographic axes and being parallel to the third. It belongs to the cubic (isometric) system.

null...## edge

Overview page. Subjects: Computing — Earth Sciences and Geography.

## fast Fourier transform

Overview page. Subjects: Earth Sciences and Geography — Probability and Statistics.

(FFT)

An algorithm (e.g. the Cooley–Tukey method) which enables the Fourier transformation of digitized wave-forms to be accomplished more rapidly by computer than would be...

## geostatistics

Overview page. Subjects: Earth Sciences and Geography — Probability and Statistics.

A subject involving ideas from geology, mathematics, mining engineering, and statistics. It is principally concerned with methods of analysis for spatial processes, the motivation being the...

## high-pass filter

Overview page. Subjects: Earth Sciences and Geography — Computing.

A filtering device that permits only those components in the frequency domain whose frequencies lie above some critical value to pass through with little attenuation, all other components...