sharee.bike-App/TINKLib/Model/Map/MapSpan.cs

using System;

namespace TINK.Model.Map
{
    /// <summary> Holds the displayed map area. </summary>
    public class MapSpan : IMapSpan
    {
        internal MapSpan(IPosition center, double radius)
        {
            if (!GetIsValid(center, radius))
                throw new ArgumentNullException();

            Center = center;
            Radius = radius;
        }

        /// <summary> Center of map displayed area.</summary>
        public IPosition Center { get; }

        /// <summary> Radius of displayed map area. </summary>
        public double Radius { get; }

        public bool IsValid => GetIsValid(Center, Radius);

        public static bool GetIsValid(IPosition center, double radius)
            => center != null 
                &&  center.IsValid  
                && !double.IsNaN(radius);
    }
}