@sakitam-gis/point-geometry

a point geometry with transforms

Installation

Requires nodejs.

$ npm install @sakitam-gis/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

var 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

• p Point the other point

Returns Point output point

sub

Subtract this point's x & y coordinates to from point, yielding a new point.

Parameters

• p Point the other point

Returns Point output point

multByPoint

Multiply this point's x & y coordinates by point, yielding a new point.

Parameters

• p Point the other point

Returns Point output point

divByPoint

Divide this point's x & y coordinates by point, yielding a new point.

Parameters

• p Point the other point

Returns Point output point

mult

Multiply this point's x & y coordinates by a factor, yielding a new point.

Parameters

• k Number factor

Returns Point output point

div

Divide this point's x & y coordinates by a factor, yielding a new point.

Parameters

• k Point factor

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 radians
• p Point Point to rotate around

Returns Point output point

matMult

Multiply this point by a 4x1 transformation matrix

Parameters

• m Array<Number> transformation matrix

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

• p Point the other point

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

• p Point the other point

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

• b Point the other point

Returns Number angle

angleWith

Get the angle between this point and another point, in radians

Parameters

• b Point the other point

Returns Number angle

convert

Construct a point from an array or point-like object if necessary, otherwise if the input is already a Point, or an unknown type, return it unchanged

Parameters

• a (Array<number> | Object | Point) any kind of input value

Examples

// this
var point = Point.convert([0, 1]);
// and this
var point = Point.convert({x: 0, y: 1});
// are equivalent to
var point = new Point(0, 1);

Returns Point constructed point, or passed-through value.