LocationExtensions.cs

public static class LocationExtensions
{
    private const double RadianHalfPiToDegrees = 90.0;
    private const double RadianPiToDegrees = 180.0;
    private const double RadianTwoPiToDegrees = 360.0;
    private static readonly Location _center = new Location(latitude: 0, longitude: 0);
    private static readonly Location _northeast = new Location(latitude: RadianHalfPiToDegrees, longitude: RadianPiToDegrees);
    private static readonly Location _southwest = new Location(latitude: -RadianHalfPiToDegrees, longitude: -RadianPiToDegrees);

    private static Location GetValidLocation(double latitude, double longitude)
    {
        // Adjust latitude if out of bounds
        while (latitude > RadianHalfPiToDegrees)
            latitude -= RadianPiToDegrees;
        while (latitude < -RadianHalfPiToDegrees)
            latitude += RadianPiToDegrees;

        // Adjust longitude if out of bounds
        while (longitude > RadianPiToDegrees)
            longitude -= RadianTwoPiToDegrees;
        while (longitude < -RadianPiToDegrees)
            longitude += RadianTwoPiToDegrees;

        var location = new Location(latitude, longitude);
        return location;
    }

    public static Location NextRandom(this Location center, double radiusDegrees, Random? random = null)
    {
        if (radiusDegrees > RadianHalfPiToDegrees) throw new ArgumentOutOfRangeException(nameof(radiusDegrees));
        random ??= new Random();
        center ??= _center;
        var diameter = radiusDegrees * 2;

        // Generate random latitude and longitude within the specified radius, with the center offset applied
        var latitude = (random.NextDouble() * diameter) - radiusDegrees + center.Latitude;
        var longitude = (random.NextDouble() * diameter) - radiusDegrees + center.Longitude;

        var location = GetValidLocation(latitude, longitude);
        return location;
    }

    public static Location NextLocation(this Random random, Location? northeast = null, Location? southwest = null)
    {
        random ??= new Random();
        northeast ??= _northeast;
        southwest ??= _southwest;

        var latDiff = Math.Abs(northeast.Latitude - southwest.Latitude);
        var latMax = Math.Max(northeast.Latitude, southwest.Latitude);
        var latitude = random.NextDouble() * -latDiff + latMax;

        var lonDiff = Math.Abs(northeast.Longitude - southwest.Longitude);
        var lonMax = Math.Max(northeast.Longitude, southwest.Longitude);
        var longitude = random.NextDouble() * -lonDiff + lonMax;

        var location = GetValidLocation(latitude, longitude);
        return location;
    }

    public static IEnumerable<Location> NextLocations(this Random random, int count)
    {
        if (random == null) throw new ArgumentNullException(nameof(random));
        if (count < 0) throw new ArgumentOutOfRangeException(nameof(count));
        return Enumerable.Range(0, count).Select(i => random.NextLocation());
    }

    public static IList<Location> NextLocationsList(this Random random, int count)
    {
        if (count < 0) throw new ArgumentOutOfRangeException(nameof(count));
        random ??= new Random();
        var locations = new List<Location>();
        for (int i = 0; i < count; i++)
        {
            var location = random.NextLocation();
            locations.Add(location);
        }
        return locations;
    }
}