Operators and functions

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

operators

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

functions

Functions express dependences between items. A function associates a single output to each input element. Some functions generate one or more subitems, see Composite function. 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 or 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 Range and 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