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The Properties property is a collection of ContextItem objects. This is how we can supply additional information needed to use the definition correctly. For example, if a ContextItemDefinition involves capturing values for latitude & longitude, it might include in the Properties a ContextItem that indicates the geodetic datum is WGS84.
NestedDefIds: Grouping Definitions The NestedDefIds property is a collection of references to other ContextItemDefinition(s). This is only populated if ValueType is set to "Nested". Sometimes there are groups of data points that need to be collected together rather than individually. For example, the Public Land Survey System is composed of 4 pieces of data the Meridian, Township, Range, and Section. Each is defined as its own ContextItemDefinition, and is represented as ContextItems that are included by value in the NestedItems property of the PLSS ContextItem.
The Presentations property is a collection of Presentation objects.: Mechanism to validate input and format display of values
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