Simple conversion between meters and nautical miles and vice versa.

Main.kt

import kotlin.math.roundToInt
import kotlin.test.assertEquals

const val PI = 3.14
const val NAUTICAL_MILE_IN_METERS = 1852
const val MEAN_EARTH_RADIUS = 6371100

fun main(args: Array<String>): Unit {
    assertEquals(NAUTICAL_MILE_IN_METERS, toMeters(1))
    assertEquals(10 * NAUTICAL_MILE_IN_METERS, toMeters(10))

    assertEquals(0.0005399568034557236, toNauticalMiles(1))
    assertEquals(0.5399568034557235, toNauticalMiles(1000))
    assertEquals(1.0, toNauticalMiles(NAUTICAL_MILE_IN_METERS))
    assertEquals(1.079913606911447, toNauticalMiles(2000))
    assertEquals(5.399568034557236, toNauticalMiles(10000))
}

fun toMeters(nauticalMiles: Int): Int = nauticalMiles * ((2 * PI * MEAN_EARTH_RADIUS) / (360 * 60)).roundToInt()

fun toNauticalMiles(meters: Int): Double = meters.toDouble() / ((2 * PI * MEAN_EARTH_RADIUS) / (360 * 60)).roundToInt()