Slot: Native Value Scale Factor (native_value_scale_factor)

CF-style packing multiplier applied when decoding the source's stored integers to physical values (physical = stored × scale_factor + add_offset). Only meaningful alongside native_units_ucum.

Tier: optional

Why this slot matters

Anyone re-reading the source grid directly (rather than the companion file) must unpack stored integers with exactly this factor; a wrong or missing factor yields physically plausible but wrong values, the worst kind of error.

In plain terms

Big datasets often save space by storing small whole numbers that must be multiplied by a constant to get the real measurement. This is that constant.

URI: envar:slot/native_value_scale_factor

Applicable Classes

Name	Description	Modifies Slot
VariableIdentity	The identity and semantics of an environmental exposure variable — what physi...	no

Properties

Type and Range

Property	Value
Range	Float
Domain Of	VariableIdentity

Cardinality and Requirements

Property	Value

Examples

Value
0.1

Comments

• Added after the reverse gap survey (docs/reverse-gap-survey.md, 2026-07): the THREDDS metadata the Amadeus flow fetches declares scale_factor = 0.1, add_offset = 220.0, _Unsigned — the packed int16 → Kelvin decode convention. The survey rated this the single most load-bearing no-home field it found: mis-decoding produces garbage temperatures, and nothing in the sidecar recorded it.

See Also

• https://cfconventions.org/cf-conventions/cf-conventions.html#packed-data

Identifier and Mapping Information

Annotations

property	value
tier	optional
justification	Anyone re-reading the source grid directly (rather than the companion file) must unpack stored integers with exactly this factor; a wrong or missing factor yields physically plausible but wrong values, the worst kind of error.
explanation	Big datasets often save space by storing small whole numbers that must be multiplied by a constant to get the real measurement. This is that constant.

Schema Source

• from schema: https://w3id.org/linkml/microschemas/envar

Mappings

Mapping Type	Mapped Value
self	envar:native_value_scale_factor
native	envar:native_value_scale_factor

LinkML Source

name: native_value_scale_factor
annotations:
  tier:
    tag: tier
    value: optional
  justification:
    tag: justification
    value: Anyone re-reading the source grid directly (rather than the companion file)
      must unpack stored integers with exactly this factor; a wrong or missing factor
      yields physically plausible but wrong values, the worst kind of error.
  explanation:
    tag: explanation
    value: Big datasets often save space by storing small whole numbers that must
      be multiplied by a constant to get the real measurement. This is that constant.
description: CF-style packing multiplier applied when decoding the source's stored
  integers to physical values (`physical = stored × scale_factor + add_offset`). Only
  meaningful alongside `native_units_ucum`.
title: Native Value Scale Factor
comments:
- 'Added after the reverse gap survey (docs/reverse-gap-survey.md, 2026-07): the THREDDS
  metadata the Amadeus flow fetches declares `scale_factor = 0.1`, `add_offset = 220.0`,
  `_Unsigned` — the packed int16 → Kelvin decode convention. The survey rated this
  the single most load-bearing no-home field it found: mis-decoding produces garbage
  temperatures, and nothing in the sidecar recorded it.'
examples:
- value: '0.1'
  description: gridMET tmmx packs Kelvin as unsigned int16 with scale 0.1
from_schema: https://w3id.org/linkml/microschemas/envar
see_also:
- https://cfconventions.org/cf-conventions/cf-conventions.html#packed-data
rank: 1000
domain_of:
- VariableIdentity
range: float