Our latest post asks the questions ‘Which reference point really matters for what you are doing?’ and ‘How accurate do you need to be to be useful?’ It seems the whole reference system for determining heights and levels in the UK wobbles around by up to 5 inches (13cm) every day due to the effect of the tides in Cornwall and similar variations occur all over the world. But has this phenomenon affected the usefulness of maps and surveyed levels?? The answer to the last question is “It depends”. To read more on this fascinating anomaly see: https://mosaicprojects.wordpress.com/2023/05/12/detail-can-be-the-enemy-of-useful/ [1]