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Author Topic:   Charting Apps for Smart Phones and Tablets
Hoosier posted 01-13-2015 09:13 PM ET (US)   Profile for Hoosier   Send Email to Hoosier  
There have been a couple of threads that have touched on the subject of NOAA charting navigation applications that are available for smart phones and tablets. The big question is about the state of the art, as far as replicating the performance of today's chartplotters. Another consideration, that's not trivial, is: do they work when disconnected from cellular data service? To be truly useful in "out of sight of land" situations the apps must work autonomously, relying only on their built-in capabilities for downloaded maps abd charts and GPS connectivity.

So, what's out there? Please comment on what you have used and how well it meets the need for autonomous navigation.

jimh posted 01-14-2015 09:30 AM ET (US)     Profile for jimh  Send Email to jimh     
There are two distinct elements involved in using a smart phone as a navigation device:

--the position finding

--the charting of that position

Let me comment about the position finding of a modern smart phone. From what I can tell, just about every modern smart phone now includes a GPS receiver. The GPS receiver is able to deduce the position from the signals it receives from satellites, just like the GPS receiver on your boat. However, these modern smart phones have an advantage: they can utilize assistance by their ability to link to a terrestrial network, typically via the cellular carrier's radio network. This assisted mode is called A-GPS (Assisted GPS).

Having A-GPS is a great benefit to position finding. Without getting into the details, with A-GPS a GPS receiver can significantly increase its sensitivity and reduce the time to first fix, compared to an unassisted GPS receiver (or what is called an autonomous GPS receiver).

A GPS receiver with A-GPS help will typically be able to utilize signals that are 20-dB weaker than the weakest signals an autonomous GPS could copy. That is a significant improvement in sensitivity, and it accounts for the ability of an A-GPS smart phone to be able to get a GPS fix even when in very bad receiving locations, such as inside a car, inside a building, or in urban canyons.

A GPS receiver with A-GPS help will typically be able to achieve a position fix solution in a matter of a few seconds from being turned on from a cold start. In comparison, an autonomous GPS receiver will need several minutes to obtain its first fix.

The A-GPS receivers in modern smart phones are really very impressive devices. However, if you take them far offshore, where they are out of range of their cellular networks and can't get assistance, they become autonomous GPS receivers. They might not work as well as your boat chart plotter's GPS receiver because the antenna in the smart phone may not be as good as the antenna in your boat GPS receiver. But the smart phone still works as an unassisted GPS. And, unless you are really far offshore or in really remote area, your smart phone will likely still be in touch with its cellular network, so it will still be operating in A-GPS mode. If you are close to shore or on some inland lake and have good cellular network signals, the smart phone will be an A-GPS receiver, and work very well.

The chart data that will be used depends on the navigation application. Some applications immediately download the map data for the position you are in. The temporarily store those maps in the smart phone memory. As your travel, they fetch more map data as needed, downloading it from their network. Applications using this mode of map data have to be connected to their network carrier to get the map data on demand. Other applications may provide a permanent storage of map data on the device. In that mode, you'd always have the map data for your region available, even if you lost your cellular network connection.

As for what I have used, I have very little experience. My smart phone is not very modern: it is an iPhone 3. And I have no cellular network service for it, no data service, no voice service. It is completely disconnected. My only connection is via WiFi.

Several years ago we were in Ireland. I took an iPhone 3 with me, planning to use it to get email when we could find an open WiFi access point to the internet. One morning we were having breakfast at our bed-and-breakfast lodging, and I happened to meet another traveler using his iPhone. He did not have a cellular connection, either. But he showed me how the iPhone would store or cache the road map data. Sitting at the B-and-B at breakfast and using the iPhone MAP application while connected via WiFi, I could get the iPhone to download all the road map data I needed for our day's travel in advance. Then, as we drove around the Irish countryside, the iPhone's GPS would show our position on the roadmap. This was a great help to us in navigation the Irish counties we were visiting. We didn't need to get a cellular connection and buy expensive voice and data services to take advantage of the iPhone's GPS and mapping capability. Of course, the maps do not stay cached very long. (I really have not seen how long they will stay in memory, but it isn't more than a few hours, I think.) This method would not be very useful for real navigation on a boat.

wally910 posted 01-14-2015 01:04 PM ET (US)     Profile for wally910  Send Email to wally910     
I have the Navionics app for my I Phone 5. I haven't gotten to test it out offshore and out of cell range yet, but it is quite good for inshore fishing. I typically use it to mark spots at low tide and come back to them, as well as to scout new spots while not on the water. I think the cost was $15.99, well worth it in my opinion.
dfmcintyre posted 01-14-2015 06:04 PM ET (US)     Profile for dfmcintyre  Send Email to dfmcintyre     
I've been using Marine US for some basic features. No complaints.
pete r posted 01-14-2015 04:48 AM ET (US)     Profile for pete r  Send Email to pete r     
Hi Hoosier. I use a marine mapping program called Navtronics. From memory it was was a derivative of a program developed in New Zealand.

I first purchased the program about four years ago when the iPad first hit the scene. It cost me about $60, and I have had endless entertainment plotting local courses from my lounge chair. At one time for example, I planned to import a yacht instead of my Boston Whaler from the US. Well, I used the charts to help investigate international waters and look at various routes I could sail back to Australia.

The program was very rudimentary when I first downloaded it, but over time it has really improved. Whenever I wish to sail or motor off to a new spot or anywhere which I am not sure of the shoreline and bottom I bring it up well before I go on my Ipad or somtimes my iPhone.I find it handy to plot preliminary and posible courses I might travel over a weekend away just to check what fuel I may need to carry.

Late last year I was out fishing with a mate in his 15-foot boat and when his dedcated fishfinder stop working he was forced to use his smart phone (his eye sight is still good), and now won't get go back to the other. He knows which channel stay in at certain water levels and his smart phone now tells him exactly where he is.

John from Madison CT posted 01-15-2015 10:37 PM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     
The Navionics application on my iPad and iPhone is excellent. It has SONAR maps now which give incredible detail. I've used it over 100 miles offshore with great results.
64nauset posted 01-19-2015 05:16 PM ET (US)     Profile for 64nauset  Send Email to 64nauset     
I would second John on the Navionics app, for [an iPhone-6] in my case. The maps aren't cheap but certainly less than chart plotter chips. This one also has a feature for driving the roads. All-in-one kind of a deal. Biggest advantage of a chart plotter over the phone is battery life, and screen size of course. Best to keep a phone plugged in while navigating. If it's not charging there's a couple hours use before non-function. Mobile phone chart plotters are batt-hogs. Modern iPhones can fully navigate via GPS without cell service.

Here's a screen shot:
(choose "original" for largest image)
Lake Lelanau area

Every feature on screen can be precisely defined by the software; lights, cans, marina phone numbers, etc. And, charts are kept up to date, so no sharpie marks all over the screen. All inland lakes included.

jimh posted 01-19-2015 11:25 PM ET (US)     Profile for jimh  Send Email to jimh     
Modern iPhones can fully navigate via GPS without cell service

The GPS receiver in a smart phone is able to work as an autonomous GPS receiver or as an Assisted-GPS. Like any A-GPS receiver, they work much better than an autonomous GPS receiver when they are in assisted-GPS mode. By better, I mean they acquire an initial position fix faster and they have increased sensitivity. These are attributes of any Assisted-GPS receiver. They are great enhancements to GPS.

The GPS receivers in most marine devices are only autonomous GPS receivers, and they cannot take advantage of the significant enhancements of A-GPS because they haven't been designed for it. Marine GPS receivers don't anticipate being in range of shore for assistance.

The GPS receivers in most modern smartphones are also able to utilize more than just the NAVSTAR GPS system. They typically can also use GLONASS, and some can use a third system, such as BEIDOU or QZSS. There is no reason to think of a smart phone as having any sort of inferiority in its GPS receiver compared to a marine GPS receiver.

Jefecinco posted 01-20-2015 09:09 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
If not for the cost of connection I would buy a smart phone to serve as, at the very least, a backup navigation device for boating and driving. Given the monthly connection charges I could pay for a nice marine MFD and vehicle GPS in a couple of years of smart phone use. So, no smart phone for me.

My trac phone costs about $108 annually with more minutes than I can possibly use. The unused minutes roll over so I have about 2500 to last me until June 30. I have a common LG flip phone and it lacks bells and whistles but does more than I require.

I would like to have a smart phone with all the useful apps but other than wanting one I can't come up with a good enough reason to justify the cost. Someday, I assume, I'll almost have to have one of the darn things. I hope the day arrives soon.


64nauset posted 01-20-2015 11:13 AM ET (US)     Profile for 64nauset  Send Email to 64nauset     
So maybe the next iteration of iPhone/pad will be:

A) Waterproof
B) NMEA compliant

iPhone, the marine version. And the $$beat$$ goes on.
Thanks for fixing my link Jim.

tedious posted 01-23-2015 11:19 AM ET (US)     Profile for tedious  Send Email to tedious     
For those who have used the Navionics ap, some questions on chart costs:

1) the ap is apparently free; how much are the charts?
2) if I already own the Navionics maps on a chip, do I have to pay a second time to get them on the ap? Is there some way to import the data?
3) if I pay for a chart, can I use it on multiple devices, or is it locked to a single phone or tablet?

Thanks for any info.


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