turf-max

turf max module

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

Calculates the maximum value of a field for a set of Point|points within a set of Polygon|polygons.

Parameters

parameter	type	description
polygons	FeatureCollection.<Polygon>	input polygons
points	FeatureCollection.<Point>	input points
inField	String	the field in input data to analyze
outField	String	the field in which to store results

Example

var polygons = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [[
          [101.551437, 3.150114],
          [101.551437, 3.250208],
          [101.742324, 3.250208],
          [101.742324, 3.150114],
          [101.551437, 3.150114]
        ]]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [[
          [101.659927, 3.011612],
          [101.659927, 3.143944],
          [101.913986, 3.143944],
          [101.913986, 3.011612],
          [101.659927, 3.011612]
        ]]
      }
    }
  ]
};
var points = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [101.56105, 3.213874]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 600
      },
      "geometry": {
        "type": "Point",
        "coordinates": [101.709365, 3.211817]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 100
      },
      "geometry": {
        "type": "Point",
        "coordinates": [101.645507, 3.169311]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [101.708679, 3.071266]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 300
      },
      "geometry": {
        "type": "Point",
        "coordinates": [101.826782, 3.081551]
      }
    }
  ]
};

var aggregated = turf.max(
  polygons, points, 'population', 'max');

var resultFeatures = points.features.concat(
  aggregated.features);
var result = {
  "type": "FeatureCollection",
  "features": resultFeatures
};

//=result

Returns FeatureCollection.<Polygon>, polygons with properties listed as outField values

Installation

Requires nodejs.

$ npm install turf-max

Tests

$ npm test