Base class that describes a coordinate (in decimal degrees)

Coordinate.kt

import kotlin.math.*

const val EARTH_RADIUS_METERS = 6378137

data class Coordinate(
    val latitude: Double,
    val longitude: Double
) {

    /**
     * @return a distance in meters between this coordinate and the passed one
     */
    fun distanceTo(to: Coordinate): Double {
        val distanceLat = Math.toRadians(to.latitude - latitude)
        val distanceLng = Math.toRadians(to.longitude - longitude)

        val a = sin(distanceLat / 2).pow(2) +
                cos(Math.toRadians(latitude)) * cos(Math.toRadians(to.latitude)) *
                sin(distanceLng / 2).pow(2)
        val c = 2 * atan2(sqrt(a), sqrt(1 - a))

        return EARTH_RADIUS_METERS.toDouble() * c
    }

    /**
     * @return a coordinate at the passed distance
     * [Source](https://gis.stackexchange.com/questions/2951/algorithm-for-offsetting-a-latitude-longitude-by-some-amount-of-meters)
     */
    fun offset(northMetersOffset: Double, eastMetersOffset: Double): Coordinate = Coordinate(
        latitude = latitude + northMetersOffset / EARTH_RADIUS_METERS * 180 / PI,
        longitude = longitude + eastMetersOffset / (EARTH_RADIUS_METERS * cos(PI * latitude / 180)) * 180 / PI
    )

    /**
     * @return north-west and south-east coordinates at the passed distance
     */
    fun getBounds(metersDistance: Double): Pair<Coordinate, Coordinate> {
        val sideLength = sqrt(metersDistance.pow(2) / 2)
        return offset(sideLength, -sideLength) to offset(-sideLength, sideLength)
    }
}