Install

npm install -g dot-density for CLI or npm install --save dot-density for use as library.

CLI

cat someCensusData.geojson | dot-density --population POP10 --sampleRate 0.1

API

FeaturePopulationCallback

Parameters

• feature Feature A geojson feature

Returns Number The feature's population

index

Produce dot density from population polygons

Parameters

• data Feature or FeatureCollection an input
• options object
  • options.population String or FeaturePopulationCallback the property key or accessor function providing each feature's population.
  • options.sampleRate [number] Number of dots per person (optional, default 1)
  • options.stochastic [boolean] If true, then use a weighted dice roll to decide wwhether to add a point when population * sampleRate yields a fractional value. (optional, default false)

Examples

var dots = require('dot-density')
var points = dots(featureCollection, { population: 'POP10' })
console.log(points) // array of Point features

Returns FeatureCollection A dot density FeatureCollection