How did the early explorers, Capt Cook for example, chart coastlines?

[sandyRoe]

I'd guess that the early attempts were fairly inaccurate.

[jno]

Cook's were pretty accurate. I'm not sure about earlier explorers, though.

This is his map of New Zealand, which he was probably the first European to visit - very little wrong with it

http://www.captcook-n...ibits/10308/10308.jpg

[wildwood]

On his South Pacific venture the purpose was to charter any lands discovered so the most accurate instruments and knowledge for that time was on hand.

127 years before that, NZ was visited by Abel Tasman but, unbeknown to them they landed on agricultural land of the Maoris so some men were killed at both sides.

[jake-the-peg]

I don't come by here all that often any more but this is quite interesting.

You start with a baseline, a measured distance between two points, the more accurate the better. then you measure the angle to the next point with a sextant or other suitable device from both ends of the baseline. You can then use trigonometry (sine rule) to get the distances of the other two lines of the triangle.

You then move to the next point and repeat.

Cook had one huge advantage - on his second and third voyages he had a copy of H4 - John Harrison's chronometer which kept extrordinarily good time and allowed for the first time accurate determination of Longitude.

Before that he'd been forced to rely on the Lunar method (http://en.wikipedia.org/wiki/Lunar_distance_
method)


This is a major reason that charts from this period suddenly look much more accurate and recognisable

Probably the gold standard in charting has to go to Bligh. Not what you'd call a good "people person" but when Cook was killed in Hawaii he got the ship and crew back home. He repeated the trick after the Bounty mutiny and eventually returned to the Torres straight creating maps of this dangerous area that were so good they were still in use up to World War II

[beso]

Much of the charting along the coast could be done very accurately with trigonometry.

[heathfield]

Cook would have used the same methods and would have obtained the same accuracies as did the Ordnance Survey, which was set up only a few years after Cook's voyages in the southern oceans. For his first published chart of New Zealand, see...

http://www.antiquemap...7174EEF732C1B5E417ADA

[wildwood]

I noticed the south island (Pounamu) is spelled different in each map, so which one is the genuine one?