Operators and functions
Operators and functions are used in expressions to calculate with data items and or literals.
An operator is a symbolic presentation of a function to be applied on operands.
Functions express dependences between items. A function associates a single output to each input element. Functions in the GeoDMS are categorized in the following function groups:
- Arithmetic: basic mathematical functions, like add, divide or sqrt
- Ordering: to compare/order data items like eq, less than, argmax or sort
- Aggregation: to aggregate data items to other domain units like sum or mean
- Conversion: to convert value types, round data items or use different notations
- Classify: to classify quantities to class units
- Transcendental: functions transcending algebra, like exponent and logarithm
- Predicates: to check conditions, like IsDefined of IsNull.
- Logical: to provide basic comparisons, returning in boolean data items like iif or and
- Relational: to relate data items of different domain units like lookup or create new domain units like unique
- Selection: to create new domain units for selections of data from other domain units like select_with_attr_by_cond
- Rescale: to scale data items to new distributions
- Constant: to define constant values like pi or true
- Trigonometric: operate on angles like sine or cosine.
- Geometric: geometric operations on points, arcs and/or polygons
- Network: to build and calculate network topologies like connect or impedance
- Grid: to calculate with data items of grid (two-dimensional) domains, like potential or district
- String: operate on data items with string value types like left or strcount
- File, Folder and Read: operate on files and folders, like MakeDir or storage_name
- Unit: to define and get information of unit items, like rangeand lowerbound
- Matrix: to perform matrix calculations, like matrix multiplication or matrix inverse
- Sequence: process data items with one-dimensional sequences.
- MetaScript:to generate script (like for_each) or request information on tree items like SubItem_PropValues
- Allocation: mainly used for Land Use Allocation
- Miscellaneous: remaining functions not categorized in other groups, like rnd_uniform or PropValue
