Mexican Charts - Arrrggghhh!

[cantxsailor]

Here I was, just yesterday, saying how amazingly accurate my SeaClear charts coupled to a GPS and using the AIS to "watch" ships running up and down the ship channel. I punched the "find boat" button on SeaClear and the chart of the area came up and I zoomed in and was surprised to be able to count the docks pictured on the chart. The blue circle denoting my boat was on the 5th dock 3/4 of the way down the dock and slightly south of the center of the dock. Where was my boat actually? "E" dock, slip 35(of about 50) and the odd numbers are on the south side of the main dock. I was very impressed as this would mean there was less than 10ft of real error in both the chart and the gps reading of my boat. Our USGS and/or NOAA are really doing a bang up job for the most part. I haven't run into anything that wasn't marked on a chart(for me to see) in ages..............m

[highseas]

Having just sailed the Baja with Navionics,and stopping at nearly every anchorage, I can tell you they are nearly spot on.Only at Isla San Geronimo did it show me on the beach when in fact I was anchored in 25ft.The only other thing I noticed was that Rocas Soledad, south of Ensenada,don't show up as a land mass.Coming into LaPaz, they were bang on.

[sded]

The Mexican charts are fine until you get South of Mazatlan', where there are no recent surveys. Errors of a couple of miles occur below there. Places like Isla Isabella, Pta Mita, ... aren't even close. Use the GPS points in one of the guidebooks then.

[barnakiel]

They are not Mexican charts.They were drawn by Columbus, whom today we still DISPUTE to be either Spanish or a Turk. Then there were many re-prints, but never corrections.

Get US Charts. Keep the Mexican ones though - they are cool deco.

b.

[sck5]

Many of the problems have nothing to do with the datum - I went to Belize last year and had what were regarded as the best paper charts in the area from the British Admiralty. But if you looked at the notes they said that large areas were "based on hand line surveys from the 1840's". There just isnt much you can do about the errors that are incorporated into a chart like that if it is what they used as the basis for the electronic charts.

However, and the original poster mentioned this, there is a cruising guide by Capt. Freya Rauscher which has sketch charts that are right on and waypoints to go with them that are also right on. I was on a charter boat with a raymarine chartplotter and had my handheld Garmin 76csx and neither of them was very good but when I programmed in Capt. Freya's waypoints I was in good shape.

[Lodesman]

Originally Posted by barnakiel

They were drawn by Columbus, whom today we still DISPUTE to be either Spanish or a Turk.

I thought he was Italian.

[Liam Wald]

Was from San Francisco. He ran a bakery in North Beach. Amerigo Vespuchi, now he was the chartmaker and widely recognized for discovering Modesto and Bakersfield.

[barnakiel]

Columbus could not be Italian. Spanish royals at that time would not fund an Italian back then. Remember the EU took off only some five centuries later.

b.

[Lodesman]

I don't think Italy yet existed as such, but am reasonably confident that Columbus came from Genova(Genoa), which is now in Northwest Italy. If you don't think the Spanish court would commission an Italian, I can't imagine how you'd figure they'd fund a Turk? As I recall there was a bit of a disagreement between the Christians and the Ottomans...

[anglooff]

I must concur with Lodesman.... As to believed birthplace. My history teacher was facinated by his story/life and if memory serves his father (or grandfather) held the honour position of gatekeeper, to one of the then important gates of the old city.

Regards

Alan

[unbusted67]

For an extension to this conversation please view this thread

http://www.cruisersforum.com/forums/...2-a-34140.html