turf.dart

THIS PROJECT IS WORK IN PROCESS

A turf.js-like geospatial analysis library working with GeoJSON, written in pure Dart.

This includes a fully RFC 7946-compliant object-representation and serialization for GeoJSON.

Most of the implementation is a direct translation from turf.js.

Get started

Get the Dart tools
Install the library with dart pub add turf
Import the library in your code and use it. For example:

import 'package:turf/helpers.dart';
import 'package:turf/src/line_segment.dart';

Feature<Polygon> poly = Feature<Polygon>(
  geometry: Polygon(coordinates: [
    [
      Position(0, 0),
      Position(2, 2),
      Position(0, 1),
      Position(0, 0),
    ],
    [
      Position(0, 0),
      Position(1, 1),
      Position(0, 1),
      Position(0, 0),
    ],
  ]),
);

main() {
  var total = segmentReduce<int>(
    poly,
    (previousValue, currentSegment, initialValue, featureIndex,
        multiFeatureIndex, geometryIndex, segmentIndex) {
      if (previousValue != null) {
        previousValue++;
      }
      return previousValue;
    },
    0,
    combineNestedGeometries: false,
  );
  print(total);
  // total ==  6
}

GeoJSON Object Model

polymorphism

Notable Design Decisions

Nested GeometryCollections (as described in RFC 7946 section 3.1.8) are not supported which takes a slightly firmer stance than the "should avoid" language in the specification

Tests and Benchmarks

Tests are run with dart test and benchmarks can be run with dart run benchmark

Any new benchmarks must be named *_benchmark.dart and reside in the ./benchmark folder.

Components

Measurement

along
area
x bbox
x bboxPolygon
x bearing
x center
centerOfMass
centroid
x destination
x distance
envelope
length
x midpoint
pointOnFeature
polygonTangents
pointToLineDistance
x rhumbBearing
rhumbDestination
rhumbDistance
square
greatCircle

Coordinate Mutation

x cleanCoords
flip
rewind
round
x truncate

Transformation

bboxClip
bezierSpline
buffer
circle
x clone - implemented as a member function of each GeoJSONObject
concave
convex
difference
dissolve
intersect
lineOffset
polygonSmooth
simplify
tesselate
transformRotate
transformTranslate
transformScale
union
voronoi
x polyLineDecode

Feature Conversion

combine
x explode
flatten
x lineToPolygon
polygonize
x polygonToLine

MISC

ellipse
kinks
lineArc
lineChunk
lineIntersect
lineOverlap
x lineSegment
lineSlice
lineSliceAlong
lineSplit
mask
x nearestPointOnLine
sector
shortestPath
unkinkPolygon

Random

randomPosition
randomPoint
randomLineString
randomPolygon

Data

sample

Interpolation

interpolate
isobands
isolines
planepoint
tin

Joins

pointsWithinPolygon
tag

Grids

hexGrid
pointGrid
squareGrid
triangleGrid

Classification

x nearestPoint

Aggregation

collect
clustersDbscan
clustersKmeans

Booleans

booleanClockwise
booleanConcave
booleanContains
booleanCrosses
booleanDisjoint
booleanEqual
booleanIntersects
booleanOverlap
booleanParallel
booleanPointInPolygon
booleanPointOnLine
booleanWithin