Scale and Temporality

Geographic scale

The intended geographic unit of this classification system is the property parcel. However it may be appropriate to map sub-parcel geographic entities for particular classes, particularly if the boundary of natural features (forests, waterways) is pertinent, if the parcel is very large, and where source data scale permits such definition. Whether to map sub-parcel areas is therefore left to operator discretion, but the intended and minimum level of attribution is the property parcel, and therefore property parcel identifiers and geographic boundaries must be present in output land use data.

Source scale

source_scale

To indicate that one of the endpoints is to be excluded from the set, use a parenthesis and not a square bracket (the latter indicates inclusion).

For example:

• If source data is precise between 0.02 m and 0.75 m, use the notation (0,1), indicating precision at the sub-metre scale, between 0–1 m (but not including the endpoints).
• If vector data is no more precise than 60 m, use [60,) if there is no suitable upper bound; or else determine an appropriate nominal upper bound (e.g. [60,x], where x > 60) since it is unlikely that in reality there is no upper bound.

Rules of thumb for converting nominal scales of input data to this notation:

• Raster data pixel size:
  Given the smaller of the pixel height or width (a) and the larger (b): [a,b].
  If a = b, this notation remains valid ([a,a] = the singleton set {a}; (a,a) would be empty).
  Example: a raster with 30 m pixels → [30,30].

• 1:50 000 scale map data:
  Precision = (map-scale denominator) / 1 000.
  Example: a 1:50 000 scale map has positional precision ≈ 50 m → [50,) (with optional practical or QA-derived upper limit).

• Derived data from mixed sources:
  A map produced from raster data with 10 m pixels, manually digitised at 1:25 000 scale →
  Precision = 10 + (25 000 / 1 000) = 35 m → [35,) (with optional upper limit).

When multiple input datasets are used together to inform a classification decision,
the ranges should be merged - compute the smallest interval that includes all given ranges
(e.g. PostgreSQL range_merge function).
Example: [1,2) and [3,4) → [1,4).

Temporality

Interannual.
A crop planted for a whole year is a commodity, but not necessarily a land use -
for instance, if it forms part of a livestock-farm system.
The primary economic purpose over an interannual period is the determining factor
for assigning a land-use class.