I hope nobody relies on Google maps for navigation!

Once upon a time perhaps when the Ordnance Survey were digitalising their paper maps they forgot our house.
Problem is that its almost impossible to persuade them they have made a mistake as their usual response is that it must be new.
No use telling them that it was on the first ever one inch Ordnance Survey of as I recall 1834.
Google earth behaves a bit oddly in Plockton.
When I was laying my mooring I downloaded a copy of the aerial photo of the harbour with the cross hairs over the mooring and noted that the lat long on the photo was about 2 miles off.
 
On a serious front, no-one should use Google Maps for navigation. The data are NOT guaranteed to be accurate, and the satellite images may well be out of position by over a hundred metres. In some places, coastline data are taken from very poor quality sources as well (Antarctica is a prime case!). Data is also not current; in fact it is frequently several years out of date - not a problem on rocky coasts, but sand/mud coasts may well have changed. There are also technical problems in the north and south, beyond about 60 degrees latitude, where the way Google handles map projections means that the representation of the data isn't accurate.

Although Google includes bathymetric information, this is NOT reliable in coastal areas, being of low resolution and taken from global geophysical datasets which are intended for the use of people studying plate tectonics.

Google is fine for a visualization of geographic information and relationships, and for looking at high resolution pictures of anchorages etc, but it should never be relied on as an accurate source of navigational information
 
AntarcticPilot said:
On a serious front, no-one should use Google Maps for navigation. The data are NOT guaranteed to be accurate, and the satellite images may well be out of position by over a hundred metres. In some places, coastline data are taken from very poor quality sources as well (Antarctica is a prime case!). Data is also not current; in fact it is frequently several years out of date - not a problem on rocky coasts, but sand/mud coasts may well have changed. There are also technical problems in the north and south, beyond about 60 degrees latitude, where the way Google handles map projections means that the representation of the data isn't accurate.

Although Google includes bathymetric information, this is NOT reliable in coastal areas, being of low resolution and taken from global geophysical datasets which are intended for the use of people studying plate tectonics.

Google is fine for a visualization of geographic information and relationships, and for looking at high resolution pictures of anchorages etc, but it should never be relied on as an accurate source of navigational information
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Would agree don't rely on it but if you have a play around with ge2kap and opencpn it can be remarkably accurate.
http://yachtvalhalla.net/navigation/googleearth.htm
I went up faversham creek recently using Google maps on a tablet and it was a godsend, luckily the images were taken at low water. Would have been aground otherwise.
 
AntarcticPilot said:
On a serious front, no-one should use Google Maps for navigation. The data are NOT guaranteed to be accurate, and the satellite images may well be out of position by over a hundred metres. In some places, coastline data are taken from very poor quality sources as well (Antarctica is a prime case!). Data is also not current; in fact it is frequently several years out of date - not a problem on rocky coasts, but sand/mud coasts may well have changed. There are also technical problems in the north and south, beyond about 60 degrees latitude, where the way Google handles map projections means that the representation of the data isn't accurate.

Although Google includes bathymetric information, this is NOT reliable in coastal areas, being of low resolution and taken from global geophysical datasets which are intended for the use of people studying plate tectonics.

Google is fine for a visualization of geographic information and relationships, and for looking at high resolution pictures of anchorages etc, but it should never be relied on as an accurate source of navigational information
Click to expand...

Yes maybe, but you wouldn't really expect them to miss out a whole island. Jura is about 30 miles long!

I like your quote of "data is frequently several years out of date". Parts of the West Coast haven't been re-surveyed since Captain Henry Otter in the 1850s, with HMS Porcupine, steam and sail.
 
NormanS said:
Yes maybe, but you wouldn't really expect them to miss out a whole island. Jura is about 30 miles long!

I like your quote of "data is frequently several years out of date". Parts of the West Coast haven't been re-surveyed since Captain Henry Otter in the 1850s, with HMS Porcupine, steam and sail.
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Well, that's obviously a gross data management error.

On the west coast, it doesn't matter all that much about old surveys; rocks don't move. But in many places it does matter; sand and mud do. Places like the Clyde estuary are certainly surveyed more frequently, though it doesn't matter all that much there - the main channel is artifically maintained anyway.
 
AntarcticPilot said:
Well, that's obviously a gross data management error.

On the west coast, it doesn't matter all that much about old surveys; rocks don't move. But in many places it does matter; sand and mud do. Places like the Clyde estuary are certainly surveyed more frequently, though it doesn't matter all that much there - the main channel is artifically maintained anyway.
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Rocks may not move, but several "new" ones have been found since these original surveys were done, - some of them the hard way!
 
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