This plat is the work of Digges and Richard Barrey (Lieutenant of Dover Castle), in order prevent choking of the Haven. It shows Dover harbour in 1581 before the new works of 1582. At this time the harbour was in need of restoration to prevent the build up of silt.The harbour and its immediate surroundings have been drawn to a scale of fifteen poles to an inch with the images of buildings superimposed. The castle is shown in detail, it was the first to make such extensive used of wall towers, a feature that has not escaped the draughtsman. The arms that appear to the left of the drawing are those of Thomas Digges, under whose command as head engineer the new works proceeded. The Crown’s engineers undertook the harbour works. The notes of anchorages have been added at a later date. (oldmapsonline)