README

loc-bind

June. 15, 2020

Ever had the urge to validate location on region based services? And wanted to validate geolocation in some sane and easy way? Don't want to use third party APIs', for whatever reason? Then loc-bind is what you're looking for!

Description

loc-bind is a tiny npm package that takes the bounded area in th form of polygon coordinates and checks if the point/location lat, long lies inside the bounded region or not.

Install

$ npm i loc-bind
or
$ yarn add loc-bind

Usage

const locBind = require('loc-bind');
// Load core loc-bind.

const polygonCoordinates = [
    [85.27268661724837, 27.703490979573274], 
    [85.27749313580306, 27.725070434748005], 
    [85.29328598248274, 27.73540274623595], 
    [85.30324234234602, 27.743607119292363], 
    [85.31854215362551, 27.745555735266393], 
    [85.3360138263724, 27.738878392849898], 
    [85.34474966274584, 27.738175490892473], 
    [85.35785341730602, 27.74204139554027], 
    [85.37702933059592, 27.740436376090585], 
    [85.38020666589044, 27.73418697607903], 
    [85.3664382129475, 27.725437213950002], 
    [85.37208680902667, 27.72324966367269], 
    [85.36369018833157, 27.71617064338767], 
    [85.35809244120152, 27.709445148471318], 
    [85.35369421131361, 27.701303205095897], 
    [85.36209083200872, 27.696346942112896], 
    [85.37288648718811, 27.698471082380422], 
    [85.35755476849451, 27.67997373762509], 
    [85.33590205625748, 27.666213135028443], 
    [85.32868376564718, 27.657939519996958], 
    [85.31382257909662, 27.66170033173455], 
    [85.30065981386609, 27.673358025817663], 
    [85.29046928594569, 27.68539046996179], 
    [85.2802787580253, 27.688022390418126], 
    [85.27136204609495, 27.69441393311658], 
    [85.27268661724837, 27.703490979573274]];

// Bounding coordinates of kathmandu valley
/* polygon coordinates(clipping boundry geojson) can be easily exported from https://export.hotosm.org/
in Geopackage .gpkg format */

const coordThamel = [85.3061304421, 27.709090497];
const coordCharikot = [86.0333332, 27.666664];

console.log(locBind.inside(coordThamel, polygonCoordinates));
// returns true as thamel lies inside kathmandu valley

console.log(locBind.inside(coordCharikot, polygonCoordinates));
// returns false as charikot doesn't lie inside kathmandu valley

Contribution ✨

Any kinds of contributions are entertained.

Inspiration

Ray Casting Algorithm

Point In Polygon

Robust Point In Polygon

Usage no npm install needed!