Abstract Class Name: Base Perimeter Data

Superclass - SEDRIS Abstract Base

Subclasses

• Feature Perimeter Data
• Feature Topology Perimeter Data
• Geometry Perimeter Data
• Sound Perimeter Data

Definition

An outline of an area, specified by the three or more Locations aggregated by a Base Perimeter Data object.

Primary Page in DRM Diagram:

• 9

Example

1. The spatial extent of a thematic coverage might be divided up into a collection of tiles. Due to political boundaries or shorelines, some of these tiles might have irregular shapes. While a rectangular tile would be described by a Base Perimeter Data object with only 4 Locations (5 if explicitly closed), an irregularly shaped tile might require a much larger number of Locations

FAQs

What is the purpose of this class?

This class allows spatial indexing regions of any shape to be defined.

How does the ordered list of Locations define the perimeter?

Just "connect the dots" from the first Location to the last Location, with an implicit line connecting the last Location back to the first Location.

Does the outline described by a Base Perimeter Data object have to be explicitly closed?

No. The outline need not be explicitly closed. If the first and last Locations are not identical, the outline is implicitly closed by connecting the last Location and the first Location.

What geometric constraints are there on the outline defined by a Base Perimeter Data object?

The outline defined by a Base Perimeter Data object must not intersect with or overlap itself, much like a Feature Edge or Geometry Edge.

Constraints

• Non Self Overlapping Perimeter Data Locations

Composed of (one-way)

• an unbounded set of {ordered} Locations[3...]