/// <summary>
    /// Returns a sorted list of CampSite instances for the given distance with an offset of +/- 5KM, sorted from east to west. The list is a copy, mofifications to the list have no affect on the original.
    /// </summary>
    /// <param name="distance">int: The distance to query</param>
    /// <returns>List of CampSite :List of matching CampSite instances, or null if none found.</returns>
    public List <CampSite> GetCampSitesByDistanceEast(int distance)
    {
        List <CampSite> campSites = _model.GetCampSites(AppDelegates.PlacesIsAtDistanceEast(distance));

        if (campSites is null)
        {
            return(null);
        }
        campSites.Sort();
        return(campSites);
    }
 /// <summary>
 /// Gets a list of TrailSite instances for the given distance with an offset of +/- 5KM (10KM range). The list is a copy, mofifications to the list have no affect on the original.
 /// </summary>
 /// <returns>List of TrailSite :List of matching TrailSite instances, or null if none found.</returns>
 public List <TrailSite> GetTrailSitesAtDistanceEast(int distance)
 {
     return(_model.GetTrailSites(AppDelegates.PlacesIsAtDistanceEast(distance)));
 }