Function:overview

= Operators and Functions =

Operators and functions are used in expressions to calculate with data items and or constants. Operators

An Operator is a symbolic presentation of a function to be applied on operands.

= Functions =

Functions express dependence between two quantities, one of which is known and the other which is produced. A function associates a single output to each input element. Functions in the GeoDMS are categorized in the following function groups, these groups correspond to the items in the table of contents:


 * function:Arithmetic are basic mathematical functions.
 * function:Ordering are used to compare/order data items.
 * Transcendental, functions which "transcends" algebra in the sense that it cannot be expressed in terms of a finite sequence of the algebraic operations of addition, multiplication, and root extraction.
 * Conversion, functions to convert data items to other value types/units or other notations.
 * Predicates, functions to check certain conditions.
 * function:Aggregation, functions to aggregate data items to other domains.
 * Logical, functions to provide basic comparisons, returning in boolean items.
 * Relational, functions to join data items of different domain units.
 * Rescale, functions to scale data items to new distributions.
 * Constants, functions to define constant values.
 * Trigonometric, (also called circular functions) are functions of an angle.
 * Point, functions used to calculate with single coordinate data items.
 * Sequence, functions used to calculate with sequences of coordinates (arcs, polygons).
 * Network, functions used to calculate with networks (nodes and links).
 * Grid, functions to calculate with grid (row/col) data.
 * String, functions used to manipulate string data items.
 * File, functions used to perform file and directory operations.
 * MetaScript, functions used to script iterations.
 * Unit, functions to be applied on unit items.
 * MiscAndMeta, other functions.