Geolib

Library to provide basic geospatial operations like distance calculation, conversion of decimal coordinates to sexagesimal and vice versa, etc.

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Install

npm install geolib

Calculates the distance between two geo coordinates

Takes 2 or 4 arguments. First 2 arguments must be objects that each have latitude and longitude properties (e.g. {latitude: 52.518611, longitude: 13.408056}). Coordinates can be in sexagesimal or decimal format. 3rd argument is accuracy (in meters). So a calculated distance of 1248 meters with an accuracy of 100 is returned as 1200 (accuracy 10 = 1250 etc.). 4th argument is precision in sub-meters (1 is meter presicion, 2 is decimeters, 3 is centimeters, etc).

Return value is always float and represents the distance in meters.

Calculates the distance between two geo coordinates but this method is far more inaccurate as compared to getDistance.

It can take up 2 to 3 arguments. start, end and accuracy can be defined in the same as in getDistance.

Return value is always float that represents the distance in meters.

Calculates the geographical center of all points in a collection of geo coordinates

Takes an object or array of coordinates and calculates the center of it.

Returns an object: {"latitude": centerLat, "longitude": centerLng}

Calculates the center of the bounds of geo coordinates.

Takes an array of coordinates, calculate the border of those, and gives back the center of that rectangle.

On polygons like political borders (eg. states), this may gives a closer result to human expectation, than getCenter, because that function can be disturbed by uneven distribution of point in different sides.

Imagine the US state Oklahoma: getCenter on that gives a southern point, because the southern border contains a lot more nodes, than the others.

Returns an object: {"latitude": centerLat, "longitude": centerLng}

Calculates the bounds of geo coordinates.

It returns maximum and minimum, latitude, longitude, and elevation (if provided) in form of an object of form:

Checks whether a point is inside of a polygon or not. Note: the polygon coords must be in correct order!

Returns true or false

Similar to is point inside: checks whether a point is inside of a circle or not.

Returns true or false

Gets rhumb line bearing of two points. Find out about the difference between rhumb line and great circle bearing on Wikipedia. Rhumb line should be fine in most cases:

http://en.wikipedia.org/wiki/Rhumb_line#General_and_mathematical_description

Function is heavily based on Doug Vanderweide's great PHP version (licensed under GPL 3.0) http://www.dougv.com/2009/07/13/calculating-the-bearing-and-compass-rose-direction-between-two-latitude-longitude-coordinates-in-php/

Returns calculated bearing as integer.

Gets great circle bearing of two points. See description of getRhumbLineBearing for more information. Returns calculated bearing as integer.

Gets the compass direction from an origin coordinate (originLL) to a destination coordinate (destLL). Bearing mode. Can be either circle or rhumbline (default). Returns an object with a rough (NESW) and an exact direction (NNE, NE, ENE, E, ESE, etc).

Sorts an object or array of coords by distance from a reference coordinate

Returns a sorted array [{latitude: x, longitude: y, distance: z, key: property}]

Finds the nearest coordinate to a reference coordinate.

Calculates the length of a collection of coordinates

Returns the length of the path in meters

Calculates the speed between two points within a given time span.

Returns the speed in options.unit (default is km/h).

Calculates if given point lies in a line formed by start and end.

Returns true or false

Converts a given distance (in meters) to another unit.

unit can be one of:

• m (meter)
• km (kilometers)
• cm (centimeters)
• mm (millimeters)
• mi (miles)
• sm (seamiles)
• ft (foot)
• in (inch)
• yd (yards)

distance distance to be converted (source must be in meter)

round fractional digits

geolib.convertUnit('km', 14213, 2) // -> 14,21

Converts a sexagesimal coordinate to decimal format

geolib.sexagesimal2decimal("51° 29' 46\" N")

Converts a decimal coordinate to sexagesimal format

geolib.decimal2sexagesimal(51.49611111); // -> 51° 29' 46.00

Returns the latitude/longitude/elevation for a given point and converts it to decimal.

Works with:

• longitude: longitude, lng, lon, 0 (GeoJSON array)
• latitude: latitude, lat, 1 (GeoJSON array)
• elevation: elevation, elev, alt, altitude, 2 (GeoJSON array)

geolib.latitude({lat: 51.49611, lng: 7.38896}); // -> 51.49611 geolib.longitude({lat: 51.49611, lng: 7.38896}); // -> 7.38896

Checks if a coordinate is already in decimal format and, if not, converts it to

Computes the destination point given an initial point, a distance (in meters) and a bearing (in degrees).

If no radius is given it defaults to the mean earth radius of 6371000 meter.

Returns an object: {"latitude": destLat, "longitude": destLng}

(Attention: this formula is not 100% accurate (but very close though))