Depthtype

Depthtype is a theoretical data type used in information organization to encode the depth relationship of elements within a hierarchical or layered structure. It provides a single depth value that can be interpreted in different ways depending on the variant: metric, ordinal, or categorical. In a metric interpretation, depthtype represents actual depth units from a defined origin. In an ordinal interpretation, it encodes the rank order of depth without implying equal intervals. In a categorical interpretation, depth values map to predefined depth labels such as surface, mid, deeper.

In data models, depthtype is distinct from spatial coordinates; it is intended to facilitate ordering, filtering, and visualization by depth while keeping separate the dimensional position from the depth attribute. Variants and constraints: metric depthtype requires a real-valued depth; ordinal uses integer ranks; categorical uses enumerated labels. Mixed forms can be supported via a structured type expressive of both category and numeric depth.

Applications of depthtype include organizing document outlines, managing scene graphs, cataloging hierarchical products, coordinating user interface layering through z-order, and handling geographic information system layers that require depth-based grouping. Its use can help separate concerns between where an element is located and how deep it appears within a visualization or structure, enabling consistent rendering and navigation.

Implementation considerations: in typed programming languages depthtype may be modeled as an algebraic data type with constructors such as Metric, Ordinal, and Categorical. Validation typically enforces non-negativity for metric depths and consistent ordering for ordinal depths. Some schemas support hybrid forms that carry both a numerical depth and a categorical label.

See also: depth map, scene graph, z-order, hierarchical modeling, ordinal type, categorical type.