iphone, GPS, Marine Charts and OS Maps.

GaryC · 10 December 2011, 19:43

I am thinking of buying a hand held chart GPS. On the RIB this will only be backup to the main chart plotter. I currently use an eTREX as backup, which has worked very well for locating wrecks for diving etc.

However I want one that will act as backup but can also be used when I go yachting (not that often) and as a full uk marine chart plotter. I would also like the unit to display OS 25K maps.

Now I have considered the Memory maps Adventurer 3500 but it has the drawback that you have to change SD cards when working between charts and OS maps.

But I am increasingly being let to the iphone which has built in GPS and if you load the charts (from Memory Map via iTunes ) and OS maps then they can all co exist on the one machine.

Is anyone using an iphone with charts and OS and indeed base map for the car. If so does it work outside of the cell network and how much iphone memory does it take?

Just looking at folks experience.

Thanks

Gary

jumpinjack · 10 December 2011, 20:13

The Navionics charts available on the iphone (or android) are great - 17quid and well worth it.

GaryC · 10 December 2011, 20:22

Quote:

Originally Posted by paulbryson75

The Navionics charts available on the iphone (or android) are great - 17quid and well worth it.

How much memory does it take on the iphone. Presumably these charts are pre loaded and will work out of the cell network range.

John Kennett · 10 December 2011, 20:51

I don't know how many megabytes it uses, but it's not a particularly significant amount.

The iPhone GPS is very slow to get a fix out of mobile coverage areas as it uses the mobile network to assist.

Get a Magellan toughcase though and you have a reliable GPS unit which is waterproof and ruggedised. They are not compatible with iPhone 4 so are getting cheaper. I picked one up off eBay for £50 and will keep my current phone when I upgrade.

Leapy · 11 December 2011, 08:22

Quote:

Originally Posted by GaryC

How much memory does it take on the iphone. Presumably these charts are pre loaded and will work out of the cell network range.

The Uk/Holland map is 285MB...don't get the Europe West, it doesn't cover all of the UK...the charts are pre-loaded...they do work out of cell range

SeaSkills · 11 December 2011, 08:44

I've got Navionics, Imray, and C-Map charts loaded on the iPad (and Navionics on iPhone), and Navionics is the best for me

Great detail, quick response - maybe loses a little detail when zoomed out, but on the whole v. good. Drains the phone battery much more than the iPad, but hasn't been a big problem as long as I don't leave the screen on too long or too bright. In the wheelhouse on the big boat I keep them connected to 12V outlets and I haven't found much to criticise - but only for occasional backup on the RIB

I use the Griffin military spec covers which work fairly well in light rain, but I don't think I'd trust them to deal with heavy rain or a thump of seawater joing me in the boat.

GaryC · 12 December 2011, 11:11

Quote:

Originally Posted by John Kennett

The iPhone GPS is very slow to get a fix out of mobile coverage areas as it uses the mobile network to assist.

I did read about this (iphone Assisted GPS) and my info so far does not indicate that an iphone is going to be any slower than any other GPS unit. The issue is that if a GPS unit when it does not know where it is, has to have the complete inventory (there is another word for this) downloaded which can take 5 mins or more at 50Baud. If the unit has been used in a recent time then it remembers the rough area and only needs the sats to give exact position. The iphone uses the cell network to get that rough position first and quickly.

So in normal use out of cell network range then it should not be any slower than a normal GPS is my understanding so far.

Gary

Poly · 12 December 2011, 11:37

Quote:

Originally Posted by GaryC

I did read about this (iphone Assisted GPS) and my info so far does not indicate that an iphone is going to be any slower than any other GPS unit. The issue is that if a GPS unit when it does not know where it is, has to have the complete inventory (there is another word for this) downloaded which can take 5 mins or more at 50Baud. If the unit has been used in a recent time then it remembers the rough area and only needs the sats to give exact position. The iphone uses the cell network to get that rough position first and quickly.

So in normal use out of cell network range then it should not be any slower than a normal GPS is my understanding so far.

Gary

Gary I think you are pretty much right. However 5 minutes seems like forever when you are waiting for it. I think the problem can appear worse with iphone (and possibly other smartphone) GPS's. Because these things zap the battery on the phone so quickly you are likely to turn it on and off more often. If they don't have a rough position from a cell network they seem to assume they are "unknown" for a starting position; whereas a handheld GPS will normally revert to its last known position (which is reasonably close to the current one will get a fix quicker).

GaryC · 12 December 2011, 18:03

Quote:

Originally Posted by SeaSkills

I've got Navionics, Imray, and C-Map charts loaded on the iPad (and Navionics on iPhone), and Navionics is the best for me

Thanks I never thought of navionics. I will look at that. Also the cases.

Gary

GaryC · 12 December 2011, 18:05

Quote:

Originally Posted by Polwart

Gary I think you are pretty much right. However 5 minutes seems like forever when you are waiting for it. I think the problem can appear worse with iphone (and possibly other smartphone) GPS's. Because these things zap the battery on the phone so quickly you are likely to turn it on and off more often. If they don't have a rough position from a cell network they seem to assume they are "unknown" for a starting position; whereas a handheld GPS will normally revert to its last known position (which is reasonably close to the current one will get a fix quicker).

Are we saying here that the iphone never remembers is rough position (old position) and has to do the long update each time you power it on. (When out of range of the cell network)

Gary

Poly · 12 December 2011, 18:28

Quote:

Originally Posted by GaryC

Are we saying here that the iphone never remembers is rough position (old position) and has to do the long update each time you power it on. (When out of range of the cell network)

Gary

That is my understanding - I don't have an iPhone to test it with, but I believe the same issue applies to some/all smartphones. And its not everytime you turn the phone on/off but every time you turn the gps feature on/off. If you have cell towers or wifi signal in range then you won't notice it (in fact it should be quicker than a normal gps in the same circumstances) but in the middle of nowhere it take a long time.

9D280 · 13 December 2011, 13:07

Yep, I got a secondhand Garmin V last used on the south coast. Took nearly 10 mins to initially work out where it was, then another 5 or 6 for a half decent "WAAS dump" for proper accuracy. Usually takes 2-3 mins now if I have for example switched off at Port Edgar & on at Largs. If same location it's usually sub 1 min. That's with 15YO technology.

The garmin instructions suggest you to do a "black start" if you have moved more than about 500 miles. This involves you telling it roughly where you are so it can start looking for the right set of satellites.