segmentEach function

void segmentEach(GeoJSONObject geojson, SegmentEachCallback callback, { bool combineNestedGeometries = true, })

Iterates over 2-vertex line segment in any GeoJSON object, similar to Iterable.forEach (Multi)Point geometries do not contain segments therefore they are ignored during this operation.

Takes FeatureCollection,Feature or GeometryObject geojson any GeoJSON a SegmentEachCallback method that takes (currentSegment, featureIndex, multiFeatureIndex, geometryIndex, segmentIndex), and a combineNestedGeometries flag that connects Polygon's geometries with each other. For example:

var polygon = Polygon(coordinates: [
     [
       Position.of([0, 0]),
       Position.of([1, 1]),
      Position.of([0, 1]),
       Position.of([0, 0]),
     ],
   ]),

Iterates over GeoJSON by 2-vertex segments segmentEach(polygon, (currentSegment, featureIndex, multiFeatureIndex, geometryIndex, segmentIndex) { //=currentSegment //=featureIndex //=multiFeatureIndex //=geometryIndex //=segmentIndex });

// Calculate the total number of segments var total = 0; turf.segmentEach(polygon, function () { total++; });

Implementation

void segmentEach(
  GeoJSONObject geojson,
  SegmentEachCallback callback, {
  bool combineNestedGeometries = true,
}) {
  int segmentIndex = 0;
  flattenEach(
    geojson,
    (Feature<GeometryType> currentFeature, int featureIndex,
        int multiFeatureIndex) {
      var geometry = currentFeature.geometry;

      if (geometry is Point) {
        return false;
      }

      if (geometry != null && combineNestedGeometries) {
        segmentIndex = _segmentEachforEachUnit(
          geometry,
          callback,
          currentFeature.properties,
          featureIndex,
          multiFeatureIndex,
          segmentIndex,
        );
      } else {
        List<List<Position>> coords = [];
        if (geometry is Polygon) {
          coords = geometry.coordinates;
        }
        if (geometry is LineString) {
          coords.add(geometry.coordinates);
        }

        for (int i = 0; i < coords.length; i++) {
          var line = LineString(coordinates: coords[i]);

          segmentIndex = _segmentEachforEachUnit(
            line,
            callback,
            currentFeature.properties,
            featureIndex,
            multiFeatureIndex,
            segmentIndex,
          );
        }
      }
    },
  );
}