plastic-geo-distance

A collection of geographic distance related utility functions.

Provides the following methods:

• Determine the bounding rectangle given a point and distance.
• Distance between two points,
• Midpoint of an array of lat/lng
• Center of minimum distance for an array of lat/lng

Types

• point: {lat: number, lng: number} in degrees
• bounds: {minLat: number, maxLat: number, minLng: number, maxLng: number} in degrees

Constructor(units: string)

Create a new instance by providing the units you are using:

• "Miles"
• "Kilometers"

Only the first character is used.

const plasticGeo = new PlasticGeoDistance('k');

Methods

bounds(distance, point)

Based on the technique by Jan Matuschek.

Returns an object:

{minLat: number, maxLat: number, minLng: number, maxLng: number}

distance(point1, point2)

Uses the Haversine formula - credit

Returns the distance between two points.

isInBounds(point, bounds)

Determining if a point is within a bounding rectangle is slightly more complex than it appears initially - bounds may encompass 0 degrees or 180 degrees longitude. This function handles this slight complexity.

Returns true if the point is withing the given bounding rectangle ( {minLat, maxLat, minLng, maxLng}), otherwise, false.

computeMidpoint(points Array<{lat:,lng:}>)

Returns a point that is the geographic center of an array of lat/lng objects (center of gravity).

computeMinimumDistancePoint(points Array<{lat:,lng:}>)

Adapted from http://www.geomidpoint.com/calculation.html - B. Center of minimum distance

Returns an object:

{ point: { lat: number, lng: number}, avgDist: number, totalDist: number }

point is the lat/lng with the minimum total distance to each point in the points array, to within less than 0.1 miles (0.161 kilometers).

Tests

Run test suite with npm test.

Issues

Please submit issues through github at mlisook plastic-geo-distance issues.

Contributions

Contributions are welcome and appreciated.

License

MIT