ericlavigne / frenet

Coordinate system adapted to road or path - measure distance along or across path

Frenet

The right coordinate system often makes things easier. In the case of a winding road, it is much easier to deal with distance along the road and distance to the right of center, rather than dealing with (x,y) coordinates.

The frenet library allows you to define such a coordinate system based on a list of (x,y) points along a path. The s coordinate measures distance along that path. The d coordinate measures distance to the right of the path.

The frenet library includes converters between (x,y) and (s,d). There are also options to convert velocity between (vx,vy) and (vs,vd).

Installation

Add the following dependency to your project.clj file:

[frenet "0.1.0"]

Usage

This code snippet demonstrates how each function is used:

(ns hello-world.core
  (:require [frenet.core :as frenet]))

(def coordinates
  (frenet/track [[0 0] [1 2] [2 3.5] [3 4.5] [4 4.5]
                 [5 4] [6 3] [7 2.7] [8 3.3] [9 4.6]]))

(frenet/xy->sd coordinates 1.0   2.0) ; [2.236 0.0]
(frenet/sd->xy coordinates 2.236 0.0) ; [1.0   2.0]

(frenet/xyv->sdv coordinates 1.0   2.0 1.5   0.5)   ; [2.236 0.0 1.216 1.036]
(frenet/sdv->xyv coordinates 2.236 0.0 1.216 1.036) ; [1.0   2.0 1.5   0.5  ]

See tests for more details.

License

Copyright © 2018 Eric Lavigne

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.