Enum: Linkage Strategy (LinkageStrategyEnum)

The spatial rule used to read an environmental value out of the exposure surface (a grid, a monitoring network, or a set of administrative areas) and assign it to one patient at their location. This is the core geographic-join decision, and it trades spatial precision against robustness to location error: a point read is precise but breaks if the geocode is wrong, whereas an area or buffer read is coarser but more forgiving. Each value below names the companion fields it makes required.

URI: envar:enum/LinkageStrategyEnum

Permissible Values

Value	Meaning	Description
point_extraction_at_residence	None	Take the single value at the exact grid cell (or interpolated point) that con...
buffer_aggregation_around_residence	None	Draw a circle of a fixed radius around the residence and summarise every valu...
area_membership_residence_in_polygon	None	Give the patient the value already attached to whichever administrative or se...
nearest_station_with_max_distance	None	Use the reading from the closest monitoring station to the residence, but onl...
population_weighted_area_to_residence	None	Combine the values over an area around the residence, but weight each part of...

Slots

Name	Description
linkage_strategy	How a gridded value is attached to a patient location

Identifier and Mapping Information

Schema Source

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

LinkML Source

name: LinkageStrategyEnum
description: 'The spatial rule used to read an environmental value out of the exposure
  surface (a grid, a monitoring network, or a set of administrative areas) and assign
  it to one patient at their location. This is the core geographic-join decision,
  and it trades spatial precision against robustness to location error: a point read
  is precise but breaks if the geocode is wrong, whereas an area or buffer read is
  coarser but more forgiving. Each value below names the companion fields it makes
  required.'
title: Linkage Strategy
from_schema: https://w3id.org/linkml/microschemas/envar
rank: 1000
permissible_values:
  point_extraction_at_residence:
    text: point_extraction_at_residence
    description: Take the single value at the exact grid cell (or interpolated point)
      that contains the patient's residence coordinates — one location in, one value
      out. The simplest and most precise strategy when the residence geocode is accurate
      and the surface is fine-grained, but also the most sensitive to geocoding error,
      since a misplaced point reads the wrong cell.
  buffer_aggregation_around_residence:
    text: buffer_aggregation_around_residence
    description: Draw a circle of a fixed radius around the residence and summarise
      every value that falls inside it into one number. This deliberately blurs the
      exact point, smoothing over geocoding uncertainty and describing a neighbourhood
      rather than a single spot, at the cost of flattening sharp local gradients.
      Requires a buffer radius (`linkage_buffer_radius_m`) and a summary function
      (`linkage_buffer_aggregation_method`, e.g. mean or max).
  area_membership_residence_in_polygon:
    text: area_membership_residence_in_polygon
    description: Give the patient the value already attached to whichever administrative
      or service-area polygon their residence falls in — for instance a census tract,
      a ZIP code, or a public water system's service area. Everyone inside the polygon
      inherits its single value regardless of where in it they live. Appropriate when
      the exposure is genuinely defined at the area level (such as a regulated water
      supply) rather than varying continuously across space. Requires a summary function
      (`linkage_buffer_aggregation_method`) stating how the polygon's value was derived.
  nearest_station_with_max_distance:
    text: nearest_station_with_max_distance
    description: Use the reading from the closest monitoring station to the residence,
      but only if that station lies within a stated maximum distance; past that cutoff
      no value is assigned rather than trusting a far-off station. Typical for sparse
      observing networks (air-quality or weather stations) where a distant station
      is not representative of local conditions. Requires the distance cutoff (`linkage_max_distance_to_station_m`),
      without which "nearest" is unbounded and the join is irreproducible.
  population_weighted_area_to_residence:
    text: population_weighted_area_to_residence
    description: Combine the values over an area around the residence, but weight
      each part of that area by how many people live there, so densely populated locations
      count for more than empty ones. The result approximates the exposure of a typical
      resident rather than a plain geographic average — useful when population is
      unevenly spread across the area. Requires a summary function (`linkage_buffer_aggregation_method`)
      for how the weighted values were combined.