a fast and fully featured open gis engine written in javascript
##Installation
npm install turf
Turf can also be run in a browser. To use it, download the minified file, and include it in a script tag.
NOTE: Browser functionality is currently unstable. Please consider using turf from node.js. Work is in progress on resolving the issues.
<script src="turf.min.js"></script>
It can also be installed using bower:
bower install turf
##Features
####geometry
####joins
####data
####measurement
####interpolation
####classification
####aggregation
####transformation
####misc
Planned Features
Additional feature requests welcomed and encouraged. To request a feature, please add a github issue with a description.
##Examples:
###load
Loads a Feature or FeaturCollection from a file.
var t = require('turf')
geojsonFile = '/path/to/file/tress.geojson'
t.load(geoJsonFile, function(err, trees){
if(err) throw err
console.log(trees)
})
###save
Saves out a feature or feature collection. 'geojson' and 'topojson' are currently supported.
var path = './testOut/poly.geojson'
var poly = t.polygon([[[0,0], [1,0], [1,1],[0,1]]])
var type = 'geojson'
t.save(path, poly, type, function(err, res){
if(err) throw err
console.log(res) // 1
done()
})
###point
Creates a geojson point Feature based on an x and a y coordinate. Properties can be added optionally.
var t = require('turf')
var point1 = t.point(-75.343, 39.984)
var point2 = t.point(-75.343, 39.984, {name: 'point 1', population: 5000})
console.log(point1)
console.log(point2)
###linestring
Creates a geojson linestring Feature based on a coordinate array. Properties can be added optionally.
var t = require('turf')
var linestring1 = t.linestring([[102.0, -10.0], [103.0, 1.0], [104.0, 0.0], [130.0, 4.0]])
var linestring2 = t.linestring([[102.0, -10.0], [103.0, 1.0], [104.0, 0.0], [130.0, 4.0]],
{name: 'line 1', distance: 145})
console.log(linestring1)
console.log(linestring2)
###polygon
Creates a geojson polygon Feature based on a coordinate array. Properties can be added optionally.
var t = require('turf')
var polygon1 = t.point([[[20.0,0.0],[101.0,0.0],[101.0,1.0],[100.0,1.0],[100.0,0.0]]])
var polygon2 = t.point([[[20.0,0.0],[101.0,0.0],[101.0,1.0],[100.0,1.0],[100.0,0.0]]],
{name: 'line 1', distance: 145})
console.log(polygon1)
console.log(polygon2)
###featurecollection
Creates a geojson FeatureCollection based on an array of features.
var t = require('turf')
var pt1 = t.point(-75.343, 39.984, {name: 'Location A'})
var pt2 = t.point(-75.833, 39.284, {name: 'Location B'})
var pt3 = t.point(-75.534, 39.123, {name: 'Location C'})
var fc = t.featurecollection([pt1, pt2, pt3])
console.log(fc)
###extent
Calculates the extent of all features and returns a bounding box.
var t = require('turf')
t.load('path/to/file/example.geojson', function(err, features){
if(err) throw err
t.extent(features, function(extent){
console.log(extent) // [minX, minY, maxX, maxY]
})
})
###square
Calculates the minimum square bounding box for another bounding box.
var t = require('turf')
var bbox = [0,0,5,10]]
t.square(bbox, function(err, square){
if(err) throw err
console.log(square) // [-2.5, 0, 7.5, 10]
})
###size
Takes a bbox and returns a new bbox with a size expanded or contracted by a factor of X.
var bbox = [0, 0, 10, 10]
t.size(bbox, 2, function(err, doubled){
if(err) throw err
console.log(doubled) // [-10, -10, 20, 20]
})
###center
Calculates the absolute center point of all features.
var t = require('turf')
t.load('path/to/file/example.geojson', function(layer, err){
if(err) throw err
t.center(layer, function(center){
console.log(center)
})
})
###bboxPolygon
Takes a bbox and returns the equivalent polygon feature.
var t = require('turf')
var bbox = [0,0,10,10]
t.bboxPolygon(bbox, function(err, poly){
if(err) throw err
console.log(poly)
})
###envelope
Takes a Feature or FeatureCollection and returns a rectangular polygon feature that encompasses all vertices.
var t = require('turf')
var pt1 = t.point(-75.343, 39.984, {name: 'Location A'})
var pt2 = t.point(-75.833, 39.284, {name: 'Location B'})
var pt3 = t.point(-75.534, 39.123, {name: 'Location C'})
var fc = t.featurecollection([pt1, pt2, pt3])
t.envelope(fc, function(err, envelopePoly){
if(err) throw err
console.log(envelopePoly)
})
###centroid
Calculates the centroid of a polygon Feature or FeatureCollection using the geometric mean of all vertices. This lessons the effect of small islands and artifacts when calculating the centroid of a set of polygons.
var t = require('turf')
var poly = t.polygon([[[0,0], [0,10], [10,10] , [10,0]]])
t.centroid(poly, function(err, centroid){
if(err) throw err
console.log(centroid) // a point at 5, 5
})
###flip
Takes a point, linestring, polygon, or featurecollection, and flips all of its coordinates from [x, y] to [y, x].
var t = require('turf')
var poly = t.polygon([[[1,0], [1,0], [1,2]], [[.2,.2], [.3,.3],[.1,.2]]])
t.flip(poly, function(err, flipped){
if(err) throw err
console.log(flipped)
})
###explode
Takes a Feature or FeatureCollection and return all vertices as a collection of points.
var t = require('turf')
var poly = t.polygon([[[0,0], [0,10], [10,10] , [10,0]]])
t.explode(poly, function(err, vertices){
if(err) throw err
console.log(vertices)
})
###combine
Combines feature collection of point, linestring, or polygon features into multipoint, multilinestring, or multipolygon features.
var t = require('turf')
var pt1 = t.point(50, 1)
var pt2 = t.point(100, 101)
var fc = t.featurecollection([pt1, pt2])
t.combine(fc, function(err, combined){
if(err) throw err
console.log(combined)
})
###isClockwise
Takes a ring and return true or false whether or not the ring is clockwise or counter-clockwise.
var t = require('turf')
var clockwiseRing = [[0,0],[1,1],[1,0],[0,0]]
var counterClockwiseRing = [[0,0],[1,0],[1,1],[0,0]]
var clockwise = t.isClockwise(clockwiseRing)
var counterClockwise = t.isClockwise(counterClockwiseRing)
console.log(clockwise) // true
console.log(counterClockwise) // false
###remove
Removes any features from a feature collection that match a property value.
var t = require('turf')
var trees = t.featurecollection([t.point(1,2, {species: 'oak'}),
t.point(2,1, {species: 'dogwood'}),
t.point(3,1, {species: 'maple'})])
t.remove(points, 'species', 'dogwood', function(err, result) {
if(err) throw err
console.log(result)
})
###filter
Keeps any features from a feature collection that match a property value.
var t = require('turf')
var trees = t.featurecollection([
t.point(1,2, {species: 'oak'}),
t.point(2,1, {species: 'birch'}),
t.point(3,1, {species: 'oak'}),
t.point(2,2, {species: 'redwood'}),
t.point(2,3, {species: 'maple'}),
t.point(4,2, {species: 'oak'})
])
t.filter(trees, 'species', 'oak', function(err, oaks){
if(err) throw err
console.log(oaks)
})
###inside
Checks to see if a point is inside of a polygon. The polygon can be convex or concave.
var t = require('turf')
var poly = t.polygon([[[0,0], [50, 50], [0,100], [100,100], [100,0]]])
var pt = t.point(75, 75)
t.inside(pt, poly, function(err, isInside){
if(err) throw err
console.log(isInside) // true
})
###within
Returns a feature collection of points representing all points that fall withing a collection of polygons.
var t = require('turf')
var poly = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.within(ptFC, polyFC, function(err, ptsWithin){
console.log(ptsWithin) // feature collection with 3 pts
})
###buffer
Buffers a point, linestring, or polygon feature to a given radius. Units supported are miles, kilometers, and degrees.
var t = require('turf')
var pt = t.point(0, 0.5)
var unit = 'miles'
t.buffer(pt, 10, unit, function(err, buffered){
if(err) throw err
console.log(buffered)
})
###distance
Calculates the distance between two point features in degrees, radians, miles, or kilometers. This uses the haversine formula to account for global curvature.
var t = require('turf')
var point1 = t.point(-75.343, 39.984)
var point2 = t.point(-75.534, 39.123)
var unit = 'miles' // or 'kilometers', 'degrees', 'radians'
t.distance(point1, point2, unit, function(err, distance){
if(err) throw err
console.log(distance)
})
###nearest
Returns the nearest point feature.
var t = require('turf')
var inPoint = t.point(-75.4, 39.4, {name: 'Location A'})
var pt1 = t.point(-75.343, 39.984, {name: 'Location B'})
var pt2 = t.point(-75.833, 39.284, {name: 'Location C'})
var pt3 = t.point(-75.534, 39.123, {name: 'Location D'})
var inFeatures = t.featurecollection([pt1, pt2, pt3])
t.nearest(inPoint, inFeatures, function(err, closestPoint){
if(err) throw err
console.log(closestPoint)
})
###tin
Takes a set of points and the name of a z-value property and creates a tin (Triangulated Irregular Network). These are often used for developing elevation contour maps or stepped heat visualizations.
var t = require('turf')
var z = 'elevation'
t.load('/path/to/pointsfeatures/elevationPoints.geojson', function(err, points){
t.tin(points, z, function(err, tin){
if(err) throw err
console.log(tin)
})
})
###grid
Takes a bounding box and a cell depth and outputs a feature collection of points in a grid.
var t = require('turf')
var depth = 15
t.grid([0,0,10,10], depth, function(err, grid){
console.log(grid) // 15x15 grid of points in a FeatureCollection
})
###planepoint
Takes a trianglular plane and calculates the z value for a point on the plane.
var t = require('turf')
var point = t.point(-75.3221, 39.529)
// triangle is a polygon with "a", "b", and "c" values representing
// the values of the coordinates in order.
var triangle = t.polygon(
[[[-75.1221,39.57],[-75.58,39.18],[-75.97,39.86]]],
{"a": 11, "b": 122, "c": 44}
)
t.planepoint(point, triangle, function(err, zValue){
if(err) throw err
console.log(zValue)
})
###midpoint
Takes two point features and returns the mid point.
var t = require('turf')
var pt1 = t.point(0,0)
var pt2 = t.point(10, 0)
t.midpoint(pt1, pt2, function(err, midpoint){
if(err) throw err
console.log(midpoint)
})
###quantile
Takes a set of features, a property name, and a set of percentiles and outputs a quantile array. This can be passed as a break array to the isolines function or the isobands function.
var t = require('turf')
var propertyName = 'elevation'
var percentiles = [10,30,40,60,80,90,99]
t.load('./testIn/Points3.geojson', function(err, pts){
if(err) throw err
t.quantile(pts, propertyName, percentiles, function(err, quantiles){
if(err) throw err
console.log(quantiles) // [ 12, 25, 29, 52, 76, 99, 143 ]
})
})
###jenks
Takes a set of features, a property name, and the desired number of breaks and outputs an array of natural breaks. This classification can be used in the isolines function or the isobands function, or for theming.
var t = require('turf')
var propertyName = 'elevation'
var num = 10
t.load('./testIn/Points3.geojson', function(err, pts){
if(err) throw err
t.jenks(pts, 'elevation', num, function(err, breaks){
if(err) throw err
done() // [ 11, 12, 18, 25, 29, 41, 50, 55, 76, 90, 143 ]
})
})
###reclass
Takes a feature collection, a in field, an out field, and an array of translations and outputs an identical feature collection with the out field property populated.
var t = require('turf')
var inField = 'elevation',
outField = 'heightIndex',
// 0 to 20 will map to 1, 20 to 40 will map to 2, etc.
translations = [[0, 20, 1], [20, 40, 2], [40, 60 , 3], [60, Infinity, 4]]
t.load('./testIn/Points3.geojson', function(err, pts){
if(err) throw err
t.reclass(pts, inField, outField, translations, function(err, outPts){
if(err) throw err
console.log(outPts)
})
})
###contour [deprecated: split into isolines for line contours and isobands for polygon filled contours]
Takes a FeatureCollection of points with z values and an array of value breaks and generates contour polygons. This is a great way to visualize interpolated density on a map. It is often used for elevation maps, weather maps, and isocrones. The main advantage over a heat map is that contours allow you to see definitive value boundaries, and the polygons can be used to aggregate data. For example, you could get the 5000 ft elevation contour of a mountain and the 10000 ft elevation contour, then aggregate the number of trees in each to see how elevation affects tree survival.
var t = require('turf')
var z = 'elevation'
var resolution = 15
var breaks = [.1, 22, 45, 55, 65, 85, 95, 105, 120, 180]
var donuts = false
t.load('../path/to/points.geojson', function(err, points){
t.contour(points, z, resolution, breaks, donuts, function(err, contours){
if(err) throw err
console.log(contours)
})
})
###isolines
Takes a FeatureCollection of points with z values and an array of value breaks and generates contour isolines. These are commonly used to create elevation maps, but can be used for general data interpolation as well.
var t = require('turf')
var z = 'elevation'
var resolution = 15
var breaks = [.1, 22, 45, 55, 65, 85, 95, 105, 120, 180]
t.load('../path/to/points.geojson', function(err, points){
t.isolines(points, z, resolution, breaks, function(err, contours){
if(err) throw err
console.log(isolines)
})
})
###isobands
Takes a FeatureCollection of points with z values and an array of value breaks and generates filled contour isobands. These are commonly used to create elevation maps, but can be used for general data interpolation as well.
var t = require('turf')
var z = 'elevation'
var resolution = 15
var breaks = [.1, 22, 45, 55, 65, 85, 95, 105, 120, 180]
t.load('../path/to/points.geojson', function(err, points){
t.isobands(points, z, resolution, breaks, function(err, contours){
if(err) throw err
console.log(isolines)
})
})
###sample
Takes a feature collection and returns N random features as a feature collection.
var t = require('turf')
var num = 10
t.load('./testIn/Points3.geojson', function(err, pts){
if(err) throw err
t.sample(pts, num, function(err, outPts){
if(err) throw err
console.log(outPts)
})
})
###tag
Performs a spatial join on a set of points from a set of polygons.
var t = require('turf')
t.load('./testIn/tagPoints.geojson', function(err, points){
t.load('./testIn/tagPolygons.geojson', function(err, polygons){
t.tag(points, polygons, 'polyID', 'containingPolyID', function(err, taggedPoints){
console.log(taggedPoints)
})
})
})
###bezier
Takes a linestring and outputs a curved version of the line.
var t = require('turf')
var resolution = 5000
var intensity = .85
var lineIn = t.linestring([
[
-80.08724212646484,
32.77428536643231
],
[
-80.03746032714844,
32.84007757059952
],
[
-80.01548767089844,
32.74512501406368
],
[
-79.95368957519531,
32.850461360442424
]
])
t.bezier(lineIn, 5000, .85, function(err, lineOut){
if(err) throw err
console.log(lineOut)
})
###simplify
Takes a feature collection of polygons or linestrings and returns a simplified version, preserving topology of shared boundaries.
var t = require('turf')
var quantization = 50
var minimumArea = 0
t.load('./path/to/complex.geojson', function(err, polys){
t.simplify(polys, quantization, minimumArea, function(err, simplified){
if(err) throw err
console.log(simplified)
})
})
###average
Calculates the average value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(5,5, {population: 200})
var pt2 = t.point(1,3, {population: 600})
var pt3 = t.point(14,2, {population: 100})
var pt4 = t.point(13,1, {population: 200})
var pt5 = t.point(19,7, {population: 300})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.average(polyFC, ptFC, 'population', 'pop_avg', function(err, averaged){
if(err) throw err
console.log(averaged.features[0].properties.pop_avg) // 400
console.log(averaged.features[1].properties.pop_avg) // 200
})
###median
Calculates the median value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(5,5, {population: 200})
var pt2 = t.point(1,3, {population: 600})
var pt3 = t.point(14,2, {population: 100})
var pt4 = t.point(13,1, {population: 200})
var pt5 = t.point(19,7, {population: 300})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.median(polyFC, ptFC, 'population', 'pop_median', function(err, medianed){
if(err) throw err
console.log(medianed.features[0].properties.pop_median) // 400
console.log(medianed.features[1].properties.pop_median) // 200
})
###sum
Calculates the sum value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.sum(polyFC, ptFC, 'population', 'pop_sum', function(err, summed){
if(err) throw err
console.log(summed.features[0].properties.pop_sum) // 900
console.log(summed.features[1].properties.pop_sum) // 1300
})
###min
Calculates the min value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.min(polyFC, ptFC, 'population', 'pop_min', function(err, minPolys){
if(err) throw err
console.log(minPolys.features[0].properties.pop_min) // 400
console.log(minPolys.features[1].properties.pop_min) // 200
})
###max
Calculates the min value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.max(polyFC, ptFC, 'population', 'pop_max', function(err, maxPolys){
if(err) throw err
console.log(maxPolys.features[0].properties.pop_max) // 500
console.log(maxPolys.features[1].properties.pop_max) // 600
})
###count
Calculates the count of points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.count(polyFC, ptFC, 'population', 'point_count', function(err, counted){
if(err) throw err
console.log(counted.features[0].properties.point_count) // 2
console.log(counted.features[1].properties.point_count) // 3
})
###deviation
Calculates the standard deviation value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.deviation(polyFC, ptFC, 'population', 'pop_deviation', function(err, deviated){
if(err) throw err
console.log(deviated.features[0].properties.pop_deviation)
console.log(deviated.features[1].properties.pop_deviation)
})
###variance
Calculates the standard deviation value of a field for points within a set of polygons.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10], [0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(1,1, {population: 500})
var pt2 = t.point(1,3, {population: 400})
var pt3 = t.point(14,2, {population: 600})
var pt4 = t.point(13,1, {population: 500})
var pt5 = t.point(19,7, {population: 200})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
t.variance(polyFC, ptFC, 'population', 'pop_variance', function(err, varianced){
if(err) throw err
console.log(varianced.features[0].properties.pop_variance)
console.log(varianced.features[1].properties.pop_variance)
})
###aggregate
Takes a set of polygons, a set of points, and an array of aggregations, then perform them. Sum, average, count, min, max, and deviation are supported.
var t = require('turf')
var poly1 = t.polygon([[[0,0],[10,0],[10,10],[0,10]]])
var poly2 = t.polygon([[[10,0],[20,10],[20,20], [20,0]]])
var polyFC = t.featurecollection([poly1, poly2])
var pt1 = t.point(5,5, {population: 200})
var pt2 = t.point(1,3, {population: 600})
var pt3 = t.point(14,2, {population: 100})
var pt4 = t.point(13,1, {population: 200})
var pt5 = t.point(19,7, {population: 300})
var ptFC = t.featurecollection([pt1, pt2, pt3, pt4, pt5])
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'
}
]
t.aggregate(polyFC, ptFC, aggregations, function(err, polys){
if(err) throw err
console.log(polys)
})
###union
Calculates the union of two polygon features or feature collections.
var t = require('turf')
t.load(__dirname + '/testIn/Intersect1.geojson', function(err, polys1){
t.load(__dirname + '/testIn/Intersect2.geojson', function(err, polys2){
t.union(polys1, polys2, function(err, unioned){
if(err) throw err
console.log(unioned)
})
})
})
###merge
Takes a feature collection of polygons and outputs a single merged polygon feature.
var t = require('turf')
t.load(__dirname + '/testIn/mergeIn.geojson', function(err, polys){
t.merge(polys, function(err, merged){
if(err) throw err
console.log(unioned)
})
})
###intersect
Calculates the intersection of two polygon features or feature collections.
var t = require('turf')
t.load(__dirname + '/testIn/Intersect1.geojson', function(err, polys1){
t.load(__dirname + '/testIn/Intersect2.geojson', function(err, polys2){
t.intersect(polys1, polys2, function(err, intersected){
if(err) throw err
console.log(intersected)
})
})
})
###erase
Returns polygon 1 minus polygon 2.
var t = require('turf')
t.load(__dirname + '/testIn/Intersect1.geojson', function(err, polys1){
t.load(__dirname + '/testIn/Intersect2.geojson', function(err, polys2){
t.erase(polys1, polys2, function(err, erased){
if(err) throw err
console.log(erased)
})
})
})
###donuts
Takes a set of overlapping polygons and returns non overlapping donuts.
var t = require('turf')
t.load('../path/to/donutsIn.geojson', function(err, donutsIn){
if(err) throw err
t.donuts(donutsIn, function(err, donuts){
if(err) throw err
console.log(donuts)
})
})
###convex
Takes a set of points and returns a convex hull polygon.
var t = require('turf')
t.load('../test/testIn/convexIn.geojson', function(err, points){
t.convex(points, function(err, hull){
if(err) throw err
fs.writeFileSync('./testOut/convex.geojson', JSON.stringify(hull))
console.log(hull)
})
})
###concave
Takes a set of points and returns a concave hull polygon.
var t = require('turf')
var maxEdge = 2.5
t.load('../test/testIn/concaveIn.geojson', function(err, points){
t.concave(points, maxEdge, function(err, hull){
if(err) throw err
console.log(hull)
})
})
This library is built and maintained by @morganherlocker :)
FAQs
a JavaScript library for performing geospatial operations with GeoJSON
We found that turf demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 9 open source maintainers collaborating on the project.
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