 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. Click here for the list of available operators.

## 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, corresponding to the table of contents:

• Arithmeticbasic mathematical functions;
• Orderingto compare/order data items;
• Transcendental: which "transcends" algebra;
• Classify: to classify data items to class domains
• Conversion:  to convert data items to other value types/units or other notations;
• Aggregation:  to aggregate data items to other domain units;
• Predicate:  to check certain conditions;
• Logical: to provide basic comparisons, returning in boolean items;
• Relational: to join data items of different domain units;
• Rescale:  to scale data items to new distributions;
• Constant:  to define constant values;
• Trigonometric: (also called circular functions) are functions of an angle;
• Point: to calculate with single coordinate data items;
• Polygons/Arcs: to calculate with vector data;
• Network: to calculate with networks (nodes and links);
• Grid: to calculate with grid (row/col) data;
• String: to manipulate string data items;
• File:  to perform file and folder operations;
• Sequence: to calculate with sequences of coordinates (arcs, polygons);
• MetaScript: to script iterations;
• Allocation: to perform land use allocation;
• Unit: to be applied on unit items;
• Miscellaneous: miscellaneous.

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