KBE3D / KBCore / turf / moranIndex

函数: moranIndex()

moranIndex(fc: FeatureCollection<any>, options: { inputField: string; threshold?: number; p?: number; binary?: boolean; alpha?: number; standardization?: boolean; }): MoranIndex

Function

Moran's I measures patterns of attribute values associated with features. The method reveal whether similar values tend to occur near each other, or whether high or low values are interspersed.

Moran's I > 0 means a clusterd pattern. Moran's I < 0 means a dispersed pattern. Moran's I = 0 means a random pattern.

In order to test the significance of the result. The z score is calculated. A positive enough z-score (ex. >1.96) indicates clustering, while a negative enough z-score (ex. <-1.96) indicates a dispersed pattern.

the z-score can be calculated based on a normal or random assumption.

Bibliography*

1. Moran's I

2. pysal

3. Andy Mitchell, The ESRI Guide to GIS Analysis Volume 2: Spatial Measurements & Statistics.

参数

fc

FeatureCollection<any>

options

inputField

string

the property name, must contain numeric values

threshold?

number

the distance threshold

p?

number

the Minkowski p-norm distance parameter

binary?

boolean

whether transfrom the distance to binary

alpha?

number

the distance decay parameter

standardization?

boolean

wheter row standardization the distance

返回

MoranIndex

示例

const bbox = [-65, 40, -63, 42];
const dataset = turf.randomPoint(100, { bbox: bbox });

const result = turf.moranIndex(dataset, {
  inputField: 'CRIME',
});