turf-min

turf min module

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

Calculates the minimum 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": [[
          [72.809658, 18.961818],
          [72.809658, 18.974805],
          [72.827167, 18.974805],
          [72.827167, 18.961818],
          [72.809658, 18.961818]
        ]]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [[
          [72.820987, 18.947043],
          [72.820987, 18.95922],
          [72.841243, 18.95922],
          [72.841243, 18.947043],
          [72.820987, 18.947043]
        ]]
      }
    }
  ]
};
var points = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [72.814464, 18.971396]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 600
      },
      "geometry": {
        "type": "Point",
        "coordinates": [72.820043, 18.969772]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 100
      },
      "geometry": {
        "type": "Point",
        "coordinates": [72.817296, 18.964253]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 200
      },
      "geometry": {
        "type": "Point",
        "coordinates": [72.83575, 18.954837]
      }
    }, {
      "type": "Feature",
      "properties": {
        "population": 300
      },
      "geometry": {
        "type": "Point",
        "coordinates": [72.828197, 18.95094]
      }
    }
  ]
};

var minimums = turf.min(
  polygons, points, 'population', 'min');

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

//=result

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

Installation

Requires nodejs.

$ npm install turf-min

Tests

$ npm test