turf-aggregate

turf aggregate module

turf.aggregate(polygons, points, aggregations)

Calculates a series of aggregations for a set of Point|points within a set of Polygon|polygons. Sum, average, count, min, max, and deviation are supported.

Parameters

parameter	type	description
polygons	FeatureCollection.<Polygon>	polygons with values on which to aggregate
points	FeatureCollection.<Point>	points to be aggregated
aggregations	Array	an array of aggregation objects

Example

var polygons = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [[
          [1.669921, 48.632908],
          [1.669921, 49.382372],
          [3.636474, 49.382372],
          [3.636474, 48.632908],
          [1.669921, 48.632908]
        ]]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [[
          [2.230224, 47.85003],
          [2.230224, 48.611121],
          [4.361572, 48.611121],
          [4.361572, 47.85003],
          [2.230224, 47.85003]
        ]]
      }
    }
  ]
};
var points = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [2.054443,49.138596]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "population": 600
      },
      "geometry": {
        "type": "Point",
        "coordinates": [3.065185,48.850258]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "population": 100
      },
      "geometry": {
        "type": "Point",
        "coordinates": [2.329101,48.79239]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [2.614746,48.334343]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "population": 300
      },
      "geometry": {
        "type": "Point",
        "coordinates": [3.416748,48.056053]
      }
    }
  ]
};
var aggregations = [
  {
    aggregation: 'sum',
    inField: 'population',
    outField: 'pop_sum'
  },
  {
    aggregation: 'average',
    inField: 'population',
    outField: 'pop_avg'
  },
  {
    aggregation: 'median',
    inField: 'population',
    outField: 'pop_median'
  },
  {
    aggregation: 'min',
    inField: 'population',
    outField: 'pop_min'
  },
  {
    aggregation: 'max',
    inField: 'population',
    outField: 'pop_max'
  },
  {
    aggregation: 'deviation',
    inField: 'population',
    outField: 'pop_deviation'
  },
  {
    aggregation: 'variance',
    inField: 'population',
    outField: 'pop_variance'
  },
  {
    aggregation: 'count',
    inField: '',
    outField: 'point_count'
  }
];

var aggregated = turf.aggregate(
  polygons, points, aggregations);

var result = turf.featurecollection(
  points.features.concat(aggregated.features));

//=result

Returns FeatureCollection.<Polygon>, polygons with properties listed based on outField values in aggregations

Installation

Requires nodejs.

$ npm install turf-aggregate

Tests

$ npm test