turf-variance

turf-variance

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

###Install

npm install turf-variance

###Parameters

name	description
polys	featurecollection of polygons
points	featurecollection of points
inField	field to map
outField	new field

###Usage

variance(polyFC, ptFC, inField, outField)

###Example

var variance = require('turf-variance')
var point = require('turf-point')
var polygon = require('turf-polygon')
var featurecollection = require('turf-featurecollection')

var poly1 = polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = featurecollection([poly1, poly2])
var pt1 = point(1,1, {population: 500})
var pt2 = point(1,3, {population: 400})
var pt3 = point(14,2, {population: 600})
var pt4 = point(13,1, {population: 500})
var pt5 = point(19,7, {population: 200})
var ptFC = featurecollection([pt1, pt2, pt3, pt4, pt5])

var varianced = variance(polyFC, ptFC, 'population', 'pop_variance')

console.log(varianced.features[0].properties.pop_variance)
console.log(varianced.features[1].properties.pop_variance)