Cartography

[JohnnyTarr]

It seems to me that one of the most important items on a ship was charts. Of course a few people sailed into the unknown without them. My question is what was the accuracy of the maps of the GAoP and what tools did a cartographer need to make a map? This goes with the Navigation thread that I have seen and I am keeping a good eye on that one too.

[jim hawkins]

The short version is, the charts were terrible! They get much better after ~1760s with the invention of shipboard chronometers so that longitude could be determined at sea. Book recomendation:

Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dava Sobel

[blackjohn]

The short version is, the charts are terrible, and they get worse with the invention of dGPS in the 1990s.

[Themarko]

Now that is the TRUTH blackjohn!

Other book recommendation The Mapmakers by John Noble Wilford

http://www.amazon.com/gp/product/039475303...glance&n=283155

[Capn_Enigma]

The short version is, the charts were terrible, yet stylish to the extreme!

[Coastie04]

Another recommended read is "Sea of Glory" by Nathaniel Philbrick. It's much later than the GAoP, and 'revolutionary new techniques' were being used, but it describes the charting process and what needed to be done in order to get accurate charts (for the day).

Coastie

[Captain Jim]

If you look at the charts of that time you will find that they are fairly accurate north-to-south and not worth a damn east-to-west. This is because they could measure ocean distance n/s using the sun but accurate e/w had to wait until the invention of a reliable chronograph.

This did in no way stop them, as the method of navigation was to travel n/s to the correct lattitude and then sail e/w until you ran into your destination. Always keep a sharp lookout when using this method.

[jim hawkins]

The short version is, the charts were terrible, yet stylish to the extreme!

True and I've tried putting some sea serpents or 'here be monsters' notes on modern charts but my bosses are never willing to go for it.

[blackjohn]

The short version is, the charts were terrible, yet stylish to the extreme!

True and I've tried putting some sea serpents or 'here be monsters' notes on modern charts but my bosses are never willing to go for it.

I once tried to keep them from removing these cool shaded relief contours from a chart. Got shot down of course.

[blackjohn]

Now that is the TRUTH blackjohn!

And I still have people tell me how much they love our charts. And how if they didn't have such and such a chart they probably wouldn't be here, etc. It's like I say, "it's just a model of reality. Not reality."

[Captain Jim-sib]

Kinda interesting, though without the accuracy of longitude, that early theories concerning continental drift came about in the mid-1600's. Once both sides of the Atlantic had been mapped, the "jig saw" fit was

observed.

[Themarko]

I like how much people trust my 'model of reality' because I used a computer to make it. And by dang if that hillshade doesn't make it look it so good they don't even ask about the all important details.