GIS Helpers

GIS Helpers is a library that provides utilities for calculating distances between geographic coordinates and checking if a point is inside a polygon. This library is built to assist with geospatial calculations such as distance between two latitude and longitude points, and checking if a point lies within a polygon.

Available in Other Languages

In addition to the JavaScript/TypeScript version, this library is also available in the following languages:

Golang

For Go developers, you can use the gis-helpers-go library to handle geographic calculations.

Repository: k6t12n/gis-helpers-go

Installation

You can install the library using either yarn or npm:

Using Yarn

yarn add @k6t12n/gis-helpers

Using npm

npm install @k6t12n/gis-helpers

Usage

Importing the Library

To use the library in your project, import the GisHelpers class:

import { GisHelpers } from 'gis-helpers';

Distance Calculation

To calculate the distance between two points, instantiate the GisHelpers class with two sets of coordinates (latitude, longitude):

const location1: [number, number] = [34.0522, -118.2437]; // Los Angeles
const location2: [number, number] = [40.7128, -74.0060];  // New York City

const distanceHelper = new GisHelpers(location1, location2);

const distanceInKm = distanceHelper.getDistance('km');
const distanceInMeters = distanceHelper.getDistance('m');

console.log(`Distance in kilometers: ${distanceInKm} km`);
console.log(`Distance in meters: ${distanceInMeters} meters`);

• The getDistance() method takes a unit parameter:
  • 'km' for kilometers
  • 'm' for meters

Point-in-Polygon Detection

To check if a specific point lies inside a polygon, use the isPointInPolygon method:

const location1: [number, number] = [34.0522, -118.2437]; // Point to check

const polygon: [number, number][] = [
    [34.0, -118.5],
    [34.2, -118.0],
    [34.5, -118.5],
    [34.0, -119.0]
]; // Example polygon

const distanceHelper = new GisHelpers(location1);

const isInside = distanceHelper.isPointInPolygon(location1[0], location1[1], polygon);
console.log(`Is the point inside the polygon? ${isInside}`);

Methods

• getDistance(unit: string): number
  Calculates the distance between two geographical coordinates in kilometers or meters.

• isPointInPolygon(latitude: number, longitude: number, polygon: [number, number][]): boolean
  Determines whether a given point (latitude, longitude) is inside a polygon defined by an array of coordinates.

Contributions

Loving the project? Please feel free to contribute to this project. Whether it's suggestions, features, code refactors, testing, any help is welcome.

License

MIT