Height Data - Grid Intervals/Resolution
The level of detail shown by any height dataset will vary depending on the density at which the height values are collected. The smaller the interval between height values, the more detailed the grid of height values and therefore the dataset that it forms.
Most height datasets are collected as a grid with an interval of between 1 metre and 5 metres between each height value. More recently however, LiDAR data has been collected at 0.5 metre and even 0.25 metre intervals in some areas.