What is @mapbox/point-geometry?
@mapbox/point-geometry is a lightweight library for handling 2D point geometry. It provides a simple API for creating and manipulating points, performing geometric operations, and calculating distances and angles between points.
What are @mapbox/point-geometry's main functionalities?
Creating Points
This feature allows you to create a new point with x and y coordinates. The code sample demonstrates how to create a point at coordinates (10, 20).
const Point = require('@mapbox/point-geometry');
const point = new Point(10, 20);
console.log(point);
Adding Points
This feature allows you to add two points together. The code sample demonstrates how to add point1 (10, 20) and point2 (5, 5) to get a new point (15, 25).
const Point = require('@mapbox/point-geometry');
const point1 = new Point(10, 20);
const point2 = new Point(5, 5);
const result = point1.add(point2);
console.log(result);
Subtracting Points
This feature allows you to subtract one point from another. The code sample demonstrates how to subtract point2 (5, 5) from point1 (10, 20) to get a new point (5, 15).
const Point = require('@mapbox/point-geometry');
const point1 = new Point(10, 20);
const point2 = new Point(5, 5);
const result = point1.sub(point2);
console.log(result);
Calculating Distance
This feature allows you to calculate the Euclidean distance between two points. The code sample demonstrates how to calculate the distance between point1 (10, 20) and point2 (13, 24).
const Point = require('@mapbox/point-geometry');
const point1 = new Point(10, 20);
const point2 = new Point(13, 24);
const distance = point1.dist(point2);
console.log(distance);
Rotating Points
This feature allows you to rotate a point around the origin by a given angle. The code sample demonstrates how to rotate a point (10, 20) by 45 degrees.
const Point = require('@mapbox/point-geometry');
const point = new Point(10, 20);
const angle = Math.PI / 4; // 45 degrees in radians
const rotatedPoint = point.rotate(angle);
console.log(rotatedPoint);
Other packages similar to @mapbox/point-geometry
point-cluster
point-cluster is a library for clustering points on a 2D plane. It provides functionality for grouping points that are close to each other. Unlike @mapbox/point-geometry, which focuses on individual point operations, point-cluster is more about managing collections of points.
point-in-polygon
point-in-polygon is a library for checking if a point is inside a polygon. It provides a simple API for performing point-in-polygon tests. While @mapbox/point-geometry focuses on point operations, point-in-polygon is specialized for spatial queries involving polygons.
turf
turf is a comprehensive geospatial analysis library that includes a wide range of functions for handling points, lines, and polygons. It offers more advanced geospatial operations compared to @mapbox/point-geometry, which is more lightweight and focused on basic point geometry.
@mapbox/point-geometry
A Point
class for representing point geometry with useful utility methods.
Installation
$ npm install @mapbox/point-geometry
API
Point
A standalone point geometry with useful accessor, comparison, and
modification methods.
Parameters
x
number the x-coordinate. This could be longitude or screen pixels, or any other sort of unit.y
number the y-coordinate. This could be latitude or screen pixels, or any other sort of unit.
Examples
const point = new Point(-77, 38);
clone
Clone this point, returning a new point that can be modified
without affecting the old one.
Returns Point the clone
add
Add this point's x & y coordinates to another point,
yielding a new point.
Parameters
Returns Point output point
sub
Subtract this point's x & y coordinates to from point,
yielding a new point.
Parameters
Returns Point output point
multByPoint
Multiply this point's x & y coordinates by point,
yielding a new point.
Parameters
Returns Point output point
divByPoint
Divide this point's x & y coordinates by point,
yielding a new point.
Parameters
Returns Point output point
mult
Multiply this point's x & y coordinates by a factor,
yielding a new point.
Parameters
Returns Point output point
div
Divide this point's x & y coordinates by a factor,
yielding a new point.
Parameters
Returns Point output point
rotate
Rotate this point around the 0, 0 origin by an angle a,
given in radians
Parameters
a
number angle to rotate around, in radians
Returns Point output point
rotateAround
Rotate this point around p point by an angle a,
given in radians
Parameters
a
number angle to rotate around, in radiansp
Point Point to rotate around
Returns Point output point
matMult
Multiply this point by a 4x1 transformation matrix
Parameters
Returns Point output point
unit
Calculate this point but as a unit vector from 0, 0, meaning
that the distance from the resulting point to the 0, 0
coordinate will be equal to 1 and the angle from the resulting
point to the 0, 0 coordinate will be the same as before.
Returns Point unit vector point
perp
Compute a perpendicular point, where the new y coordinate
is the old x coordinate and the new x coordinate is the old y
coordinate multiplied by -1
Returns Point perpendicular point
round
Return a version of this point with the x & y coordinates
rounded to integers.
Returns Point rounded point
mag
Return the magnitude of this point: this is the Euclidean
distance from the 0, 0 coordinate to this point's x and y
coordinates.
Returns number magnitude
equals
Judge whether this point is equal to another point, returning
true or false.
Parameters
other
Point the other point
Returns boolean whether the points are equal
dist
Calculate the distance from this point to another point
Parameters
Returns number distance
distSqr
Calculate the distance from this point to another point,
without the square root step. Useful if you're comparing
relative distances.
Parameters
Returns number distance
angle
Get the angle from the 0, 0 coordinate to this point, in radians
coordinates.
Returns number angle
angleTo
Get the angle from this point to another point, in radians
Parameters
Returns number angle
angleWith
Get the angle between this point and another point, in radians
Parameters
Returns number angle
angleWithSep
Find the angle of the two vectors, solving the formula for
the cross product a x b = |a||b|sin(θ) for θ.
Parameters
Returns number the angle in radians
convert
Construct a point from an array if necessary, otherwise if the input
is already a Point, or an unknown type, return it unchanged
Parameters
Examples
var point = Point.convert([0, 1]);
var point = new Point(0, 1);
Returns Point constructed point, or passed-through value.