The connection to Drake is reported by Sr. William Monson Admiral in his manuscript at the Bodelian in Oxford naming Dudley as a commander of the Maryrose, a 600 ton vessel with a crew of 250 men, and was knighted by Lord Essex at the battle of Cadiz. Further while I am not certain , he is reported to have married the daughter of Cavendish. To move on , what was contemporary with Drakes thought on the Pacific Northwest would have been what influenced Dudley the most. The maps he made of the Pacific coast carry far to much detail to not have been transcribed from Drakes work.
Drake is reported to have felt that the land veered off towards meeting with Asia.
This would help to explain how that part of the Pacific was reduced in width. Since the date on the map is when it was printed , we must account for the preparation of drawings the mathematics of transcribing information from a log to a piece of paper , the finding of a competent engraver, and the long tedious process of engraving a plate.