Underlay concepts and uses

Some concepts for talking about underlays and overlays:

  • A piece of knowledge is an observation, assertion, or a synthesis / interpolation of other pieces.
  • A layer of knowledge is a collection united by shared properties (type, detail, origin, other scope)
  • An overlay is a lens: a layer that summarizes, synthesizes, organizes knowledge from other layers for an audience (a view, map, essay, journal)
  • An underlay is a granular layer, that can support many overlays. (a taxonomy, language, reference, database, collection, normalized dataset)
  • An interlay is a map among layers
  • A mesh, applied to a layer, is a space of combinations of layer properties. This can include a distance measure for each property-dimension and a characteristic grain size or smallest distance between two distinguished points. A layer with pieces corresponding to every point in a mesh is completed with respect to that mesh.

These terms depend on context: an overlay in one context can be an underlay in another. Synthetic overlays can stack, each adding synthesis and interpretation to the next. An underlay is itself an overlay of its individual components, structured for clarity into a layer.

Some ways to think about the effectiveness of an underlay of pieces:

  • the compression it allows for descriptions. [identifying widely-used elements]
  • its precision in describing dependencies [references, assumptions, methods]
  • the cleanliness of clustered components [standardizing + referencing components and arguments]
  • the clarity of the dataspace defined by the layer [clear motivation, existing data sources that map onto it]
  • the completability of that dataspace [ways to generate new elements; gaps for interpolation + future observation]
  • the ease of reorganizing , updating, and recompiling those pieces when elements change.