Settlement Spacing Nearest Neighbor Index

Clark Evansnearest-neighbor point pattern index on explicit local planar study area, no edge correction/inferred spatial significance or contemporaneity. Caller independently establishes sample/context/calibration applicability; not definitive chronology, provenance, taxonomy, disease or human identity.

Description

Nearest-neighbor spacing compares observed settlement distances with a declared study-window baseline.

Nearest-neighbor spacing compares observed settlement distances with a declared study-window baseline.^[1]

Its index depends on sampling boundaries and does not by itself establish settlement processes. Use Settlement Spacing Nearest Neighbor Index to evaluate the supplied inputs under the model explained below.

When to use Settlement Spacing Nearest Neighbor Index

Use Settlement Spacing Nearest Neighbor Index to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.

How to use Settlement Spacing Nearest Neighbor Index and understand its results

Establish the units, measurement scope and model assumptions before entering values.
Enter Observed settlement planar positions meters, Caller study window area m2 using the field table and validation rules below, then run the tool.
Read Observed mean nearest neighbor meters, Poisson expected nearest neighbor meters, Nearest neighbor index; interpret the units, signs, ordering and unknown-value placeholders described below.
Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.

Input field	Meaning	Value type	Requirement
observedSettlementPlanarPositionsMeters	Observed settlement planar positions meters	array of array	Required; constraints below
callerStudyWindowAreaM2	Caller study window area m2	number	Required; constraints below

Enter at least two finite planar [x,y] settlement points in m and a positive study-window area in m². For each point take the nearest other Euclidean distance, average them, then compute Poisson baseline 0.5/sqrt(n/area). Return observed mean, baseline and their ratio. Coincident points are accepted and can give zero distances. No edge correction, significance test or check that points lie within a supplied boundary occurs.

index=meanNearestNeighbor/(0.5/sqrt(pointCount/studyAreaM2))

Use the field order, units and branch conditions described above.

Output field	Meaning	Value type
observedMeanNearestNeighborMeters	Observed mean nearest neighbor meters	number
poissonExpectedNearestNeighborMeters	Poisson expected nearest neighbor meters	number
nearestNeighborIndex	Nearest neighbor index	number

json

{
  "input": {
    "observedSettlementPlanarPositionsMeters": [
      [
        0,
        0
      ],
      [
        3,
        0
      ]
    ],
    "callerStudyWindowAreaM2": 36
  },
  "output": {
    "observedMeanNearestNeighborMeters": 3,
    "poissonExpectedNearestNeighborMeters": 2.1213203435596424,
    "nearestNeighborIndex": 1.4142135623730951
  }
}

Limitations and assumptions

Its index depends on sampling boundaries and does not by itself establish settlement processes. Apply the exact scope and assumptions explained above.

All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.

Alternative or Complementary methods

Use Site Size From Artifact Scatter Calculator for a related task: An artifact scatter's convex hull encloses its measured outer points.

Use Knapping Floor Refit Cluster Density Calculator for a related task: Refit-cluster density combines independently assigned clusters with a surveyed floor area.

References

Settlement Spacing Nearest Neighbor Index — tool.io

Similar or alternative tools

Site Size From Artifact Scatter Calculator
An artifact scatter's convex hull encloses its measured outer points.
Knapping Floor Refit Cluster Density Calculator
Refit-cluster density combines independently assigned clusters with a surveyed floor area.