A library for area, distance, heading measurements (spherical_util.dart if port from android-maps-utils).

In your dart/flutter project add the dependency:

 dependencies:
   ...
   maps_toolkit: ^2.0.0

A simple usage example:

import 'package:maps_toolkit/maps_toolkit.dart';

main() {
  val distanceBetweenPoints = SphericalUtil.computeDistanceBetween(
    LatLng(51.5073509, -0.1277583),
    LatLng(48.856614, 2.3522219)
  );
}

Usage with Google Maps package (specify a prefix for an import):

import 'package:maps_toolkit/maps_toolkit.dart' as mp;
import 'package:google_maps/google_maps.dart';
import 'package:test/test.dart';

void main() {
  final pointFromToolkit = mp.LatLng(90, 0);
  final pointFromGoogleMap = LatLng(90, 0);

  mp.SphericalUtil.computeAngleBetween(pointFromToolkit, pointFromToolkit);
}

• SphericalUtil.computeArea - calculate the area of a closed path on Earth.

• SphericalUtil.computeDistanceBetween - calculate the distance between two points, in meters.

• SphericalUtil.computeHeading - calculate the heading from one point to another point.

• SphericalUtil.computeLength - calculate the length of the given path, in meters, on Earth.

• SphericalUtil.computeOffset - calculate the point resulting from moving a distance from an origin in the specified heading (expressed in degrees clockwise from north).

• SphericalUtil.computeOffsetOrigin - calculate the location of origin when provided with a point destination, meters travelled and original heading.

• SphericalUtil.computeSignedArea - calculate the signed area of a closed path on Earth.

• SphericalUtil.interpolate - calculate the point which lies the given fraction of the way between the origin and the destination.

• PolygonUtil.containsLocation - computes whether the given point lies inside the specified polygon.

• PolygonUtil.isLocationOnEdge - computes whether the given point lies on or near the edge of a polygon, within a specified tolerance in meters.

• PolygonUtil.isLocationOnPath - computes whether the given point lies on or near a polyline, within a specified tolerance in meters.

• PolygonUtil.locationIndexOnPath - computes whether (and where) a given point lies on or near a polyline, within a specified tolerance.

• PolygonUtil.locationIndexOnEdgeOrPath - computes whether (and where) a given point lies on or near a polyline, within a specified tolerance.

• PolygonUtil.simplify - simplifies the given poly (polyline or polygon) using the Douglas-Peucker decimation algorithm.

• PolygonUtil.isClosedPolygon - returns true if the provided list of points is a closed polygon.

• PolygonUtil.distanceToLine - computes the distance on the sphere between the point p and the line segment start to end.

• PolygonUtil.decode - decodes an encoded path string into a sequence of LatLngs.

• PolygonUtil.encode - encodes a sequence of LatLngs into an encoded path string.

Please file feature requests and bugs at the issue tracker.