Can I trust my iPad as a chart plotter?

[marklucas]

We're long past the days of WGS datum errors with modern charts

But was the original survey correct?

I've lost count of the number of times GPS has shown a position a significant distance (>0.5 NM) from where we were physically - and yes the GPS (four of them in once case) were using the correct datum.

To be honest, I can't remember the last time I actually used GPS to navigate.

 

[vyv_cox]

In both the Ionian and Aegean seas the Navionics app on my iPad is considerably more accurate that the Garmin charts on my plotter. Not only is the cartography far more detailed but the position of the chart relative to reality is remarkably better. Garmin cartography in these areas has not been updated for at least ten years, maybe considerably more and many recent features are not shown, whereas they are on Navionics.

 

[ParaHandy]

hi,
I just checked my ipad for the same spot and it appears to be accurate with the navigation marks in the right place

I just downloaded that area again and everything corrected itself. Hmmm .... lesson appears to be to refresh the areas you need.

Thanks for pointing that out, Rab. Very useful.

 

[Neil_Y]

I can't quite believe any one trusts electronics and man made maps over eyeball to this sort of accuracy. I also found errors (serious and dangerous if you'd just believed the chart) on Imray, but as the charts are transposed by hand they can make mistakes, those mistakes can end up on electronic versions.

If it's a hard rock I'd be giving it at least 50' or probably 100' if I was new to the area, unless I could see it. I also started navigating with dr. GPS can be incredibly accurate but can also loose the accuracy when you need it without any warning, charts should also be treated with caution unless you know they are correct. All the nav aids are aids not navigators.

 

[Sailfree]

I can't quite believe any one trusts electronics and man made maps over eyeball charts .

my problem is that my eyeballs do not work in the dark nor for underwater rocks.

 

[dgadee]

If it's a hard rock I'd be giving it at least 50' or probably 100' if I was new to the area, unless I could see it.

Of course anyone would be as careful. But you can use electronic navigation at the same time as your eyes. Having said that, when I used to use paper and log you never really knew where you were. You hoped you knew, but could easily be substantially away from that position when in poor visability.

 

[Benjaminer]

So the conclusion here from your above discussion is that we cant rely 100 % on the electronic gadgets for happening best. Then , my question is if these things are not doing good in case of our emergency , why such apps are installed. BTW I have iPhone and till not used this feature.

 

[ParaHandy]

The channel markers are all over the place and our track, well say no more!

Could you d/l the local map area of Omloop again and a) see if the channel markers are in the correct position and, b) does the track change to one resembling the actual track.

 

[Emjaytoo]

Could you d/l the local map area of Omloop again and a) see if the channel markers are in the correct position and, b) does the track change to one resembling the actual track.

Just pulled this off the iPad this evening.

If you look at the wider picture, it's pretty accurate, the track through the lagoon at Bastiaan De Langeplaat is spot on, maybe a bit tight on the exit at the northern end. At the southern end of the lagoon, you can see where we went on the jetty and that is bang on!

So what's happening in the Omloop?

 

[ParaHandy]

Do MENU then download and load a new/later version of the chart and see what you get. The chart you've got there is the old one.

 

[Emjaytoo]

Do MENU then download and load a new/later version of the chart and see what you get. The chart you've got there is the old one.

Didn't quite understand first time around. Have now reloaded the charts and the channel markers are now correct. Track is still wrong, but that is historical, will have to re-run the route next time over in Holland.

 

[ParaHandy]

Have now reloaded the charts and the channel markers are now correct. Track is still wrong

Thanks ..... track error unlikely to come from the underlying chart? I was bothered by the GPS accuracy some time ago and from a lot of scratching around - mainly google - I read a sort of off-hand remark that to save battery power, the iPad GPS was not powerful enough to track multiple satellites and would settle for a minimum number and thus be less accurate; especially so when it had no wifi signal (wifi data has position info in it, apparently).

All very interesting. Will have to remember to reload the charts regularly.

 

[erbster]

Parahandy- I wonder if the same is true for the iPhone? I am guessing not; I use Navionics on that, mostly to keep a historical record, and the track logs on that seem spot on. Chews the battery up something rotten of course.

 

[Sailfree]

At SIB bought a waterproof case for i phone and i pad.

Demonstrated also dropping iphone on the concrete with no damage - not proving it with mine though

 

[erbster]

I saw those cases, but thought them a little pricey. The new iphone is a different shape and if (when?) I upgrade.....

 

[Hadenough]

At SIB bought a waterproof case for i phone and i pad.

Demonstrated also dropping iphone on the concrete with no damage - not proving it with mine though

What brand? I've been waiting months for Scanstrut to release their iPad 3 version.

 

[Cardo]

What brand? I've been waiting months for Scanstrut to release their iPad 3 version.

It's out. Mine turned up in the post yesterday.