private IEnumerable<SizeLegendItemDto> CreateContinuousSizeLegendItems(SizeMap map, double lowerSize, double upperSize)
        {
            var unit = (upperSize - lowerSize) / 2;

            for (var i = 0; i < ContinuousItems; i++)
            {
                var itemDto = new SizeLegendItemDto()
                {
                    Size = lowerSize + (i * unit),
                    Label = GetLabelName((int?) map.MapInverse(i * unit))
                };

                yield return itemDto;
            }
        }
        private IEnumerable <SizeLegendItemDto> CreateContinuousSizeLegendItems(SizeMap map, double lowerSize, double upperSize)
        {
            var unit = (upperSize - lowerSize) / 2;

            for (var i = 0; i < ContinuousItems; i++)
            {
                var itemDto = new SizeLegendItemDto()
                {
                    Size  = lowerSize + (unit * i),
                    Label = (string)map.MapInverse(i * 0.5d)
                };

                yield return(itemDto);
            }
        }