protected override SpatialPrefixTree NewSPT()
 {
     return(new GeohashPrefixTree(ctx, maxLevels != null ? maxLevels.Value : GeohashPrefixTree.GetMaxLevelsPossible()));
 }
            protected override int GetLevelForDistance(double degrees)
            {
                var grid = new GeohashPrefixTree(ctx, GeohashPrefixTree.GetMaxLevelsPossible());

                return(grid.GetLevelForDistance(degrees));
            }