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Random coordinates for Google Maps with Typescript

 3 years ago
source link: https://marco.dev/2018/03/16/google-maps-typescript/
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Random GPS Coordinates for Google Maps in TypeScript

What’s for?

I’m developing a small Mobile Application using Ionic and Angular. The app uses a Map to show to the user some nearby services.

For the test phase, as you can imagine, we don’t have real service to show and the user/demo can be anywhere.

To help with the test I created a simple generator of GPS coordinates based on the location of the user.

Here the package NPM and the code source GitHub

map_1.jpg

The coordinates of the 3 cook’s hats are generated from the library. The green point is the current position.

You can test the app yourself (alpha on google play store):

https://play.google.com/apps/testing/com.wicooks.next

How to use it

The library is still a work in progress but already working.

You simply need the starting coordinates (latitude/longitude) and pass the maximum number of kilometers of distance for the new coordinates.

The coordinates are created using this function:

import {LatLng as LatitudeLongitude} from "@molteni/coordinate-utils/dist/LatLng";

 generateCoordinates() : LatitudeLongitude {
    return RandomCoordinateUtils.randomCoordinateFromPositionWithExplicitLatLng(this.currentLocation.lat, this.currentLocation.lng, 0.1);
  };

To the current location are added/subtracted 0 to 100 meters to the longitude and latitude.

How it works

The calculation is not extremely accurate but is enough for the Use Cases of most developers.


const EARTH_RADIUS = 6378;

    export function addKMToLatitude(latitude : number, kilometers : number) : number {
        return latitude + (kilometers / EARTH_RADIUS) * (180 / Math.PI);
    }

    export function addKMToLongitude(latitude : number, longitude : number, kilometers : number) : number {
        return longitude + (kilometers / EARTH_RADIUS) * (180 / Math.PI) / Math.cos(latitude * Math.PI / 180);
    }

    export function  getKMperDegree() {
        return (2*Math.PI / 360) * EARTH_RADIUS;
    }
}

Author

Marco Molteni

Marco Molteni Blog


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