turf-deviation

turf deviation module

turf.deviation(polygons, points, inField, outField)

Calculates the standard deviation value of a field for points within a set of polygons.

Parameters

parameter	type	description
polygons	FeatureCollection	a FeatureCollection of Polygon features
points	FeatureCollection	a FeatureCollection of Point features
inField	String	the field in points from which to aggregate
outField	String	the field to append to polygons representing deviation

Example

var polygons = turf.featurecollection([
  turf.polygon([[
    [-97.807159, 30.270335],
    [-97.807159, 30.369913],
    [-97.612838, 30.369913],
    [-97.612838, 30.270335],
    [-97.807159, 30.270335]
  ]]),
  turf.polygon([[
    [-97.825698, 30.175405],
    [-97.825698, 30.264404],
    [-97.630691, 30.264404],
    [-97.630691, 30.175405],
    [-97.825698, 30.175405]
  ]])
]);
var points = turf.featurecollection([
  turf.point([-97.709655, 30.311245],
    {population: 500}),
  turf.point([-97.766647, 30.345028],
    {population: 400}),
  turf.point([-97.765274, 30.294646],
    {population: 600}),
  turf.point([-97.753601, 30.216355],
    {population: 500}),
  turf.point([-97.667083, 30.208047],
  {population: 200})
]);
 
var inField = 'population';
var outField = 'pop_deviation';
 
var deviated = turf.deviation(
  polygons, points, inField, outField);
 
var result = turf.featurecollection(
  points.features.concat(deviated.features));
 
//=result

Installation

Requires nodejs.

$ npm install turf-deviation

Tests

$ npm test