turf.dart

Looking for maintainers as a work student position in Germany: Write an email to [email protected]

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),
    ],
  ]),
);

void 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

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
• [x] area
• [x] bbox
• [x] bboxPolygon
• [x] bearing
• [x] center
• [ ] centerOfMass
• [x] centroid
• [x] destination
• [x] distance
• [ ] envelope
• [ ] length
• [x] midpoint
• [ ] pointOnFeature
• [ ] polygonTangents
• [ ] pointToLineDistance
• [x] rhumbBearing
• [x] rhumbDestination
• [x] 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
• [x] polygonSmooth
• [ ] simplify
• [ ] tesselate
• [x] 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

META

• [x] coordAll
• [x] coordEach
• [x] coordReduce
• [x] featureEach
• [x] featureReduce
• [x] flattenEach
• [x] flattenReduce
• [x] geomEach
• [x] geomReduce
• [x] propEach
• [x] propReduce
• [x] segmentEach
• [x] segmentReduce
• [x] getCluster
• [x] clusterEach
• [x] clusterReduce

Invariants

• [x] getCoord
• [x] getCoords
• [x] getGeom

Booleans

• [x] booleanClockwise
• [x] booleanConcave
• [x] booleanContains
• [x] booleanCrosses
• [x] booleanDisjoint
• [x] booleanEqual
• [x] booleanIntersects
• [ ] booleanOverlap
• [x] booleanParallel
• [x] booleanPointInPolygon
• [x] booleanPointOnLine
• [ ] booleanWithin

Unit Conversion

• [x] bearingToAzimuth
• [x] convertArea
• [x] convertLength
• [x] degreesToRadians
• [x] lengthToRadians
• [x] lengthToDegrees
• [x] radiansToLength
• [x] radiansToDegrees
• [ ] toMercator
• [ ] toWgs84