iPhone navigation apps.

[rikhall]

Originally Posted by bjung

Dave,
Is the ActiveCaptain info in the Charts &Tides app loaded or does it require cell connection/ wifi to retrieve info?

Bernd

Loaded

Rik

[hellosailor]

"Unfortunately the phone GPS won't acquire a signal in airplane mode. There is no error message "
Because there is no error. GPSes are among the prohibited devices on aircraft, because most of them can and do "leak" some signal. (Probably from something akin to a superhet stage in the receiver.)
I'd be surprised if there isn't a way to shut the cellular radio and allow the GPS to keep running, but cell phones are full of surprises.

AFAIK no cell phone with a GPS uses a WAAS-enabled GPS, so they will always be less accurate than a "real" commodity grade GPS these days. And on the Verizon system, or any CDMA-based system, they are set up so an incoming voice call will SUSPEND THE DATA SERVICES. If your phone is using the A-GPS modes, that should mean a larger GPS error while the voice call is in progress, too.

WRT the phone chewing up the battery when there is no call signal to be found, that's also normal. On the Palm Treos there are applications that can tell the phone to shut down cellular radio when there is a loss of signal, there's probably something similar for the iPhone since all cell phones work about the same way there: When there's no signal, they ramp up to high power (600mW) and keep trying to ping a tower. When they get a signal, they ramp down to the lowest power that will keep a connection. That's why cell phones today get 5x-10x more standby time than cell phones did a decade ago, they all implement this in similar ways.

Dedicated chartplotters aren't obsolete, yet.

[Jim H]

I had the Navionics charts on my earlier generation UK iPhone when I was sailing in the San Juans, but I didn't like them much because the GPS didn't seem to want to work. I didn't want to connect to the 3G data network with a phone from out of country (a 7 quid charge per connect), but then it seemed like the GPS was disabled without it.

Here in the UK with a 3GS iPhone, Memory Map software is very slick. For 40 quid, you get the Admiralty Charts of the entire UK (on both your PC and one mobile device, like an iPhone or iPad), and the GPS tracks well (at least when 3G data is around).

I also have a Wi-Fi only iPad, for which there is a GPS plug in module that is about $100. I'm wondering if the module would do better (being designed to work without a 3G network) meaning that I could have my Admiralty charts, a larger screen, and a GPS without needing any data network. I"m still tempted to try that...

Welcome to Memory-Map Navigation Software : Digital Maps for PCs and Pocket PCs

Bad Elf | Tools and Toys for Your iPod touch, iPhone, and iPad

[hellosailor]

Jim, most cell phone GPSes are preset to use A-GPS modes. "A" for "Assisted" with information either form the cellular network, or local wifi networks, or both. If they can identify a local Wifi router, that information goes out to a database of WiFi fixed locations and gets used for a quick rough position fix. Meanwhile, they may be using the cellular towers for a rough fix (if there's no better information) or to hot start the GPS data, or to process the data from the satellites instead of processing it in the phone.

One can argue that this is done to enhance profits ($$data plans) rather than performance but that's not relevant here. the point is, they all are set up to use A-GPS modes out of the box. And they all CAN be modified to run in "Standalone" mode now, although older phones locked this out, and the setup menus are often hidden and "secret".

So you certainly should be able to set up your cell phone to use GPS in standalone mode. But a $50 (not 100 in the US) standalone Bluetooth GPS will be WAAS-enabled and it will work better than whatever is in the cell phone anyway. It is just "more stuff" to deal with, but it can be located where it will get a better signal than your cell phone, with no water damage worries for the tablet.

[SVAuspicious]

Originally Posted by bjung

Is the ActiveCaptain info in the Charts &Tides app loaded or does it require cell connection/ wifi to retrieve info? How precise is the GPS without cell/wifi service?

As rikhall noted, the ActiveCaptain data in Charts & Tides is completely available offline.

The understanding y'all have of AGPS is way different from mine. My understanding is the phone uses the cell phone tower locations to get close and seed the GPS solution. Once the GPS has a location there is no other data in to the algorithms except the satellite information. The response of the mapping and navigation apps is consistent with my understanding.

If anyone has definitive, sourced data to the contrary I'd be pleased to see it. I'll try and wake up some of my old colleagues and see if something has changed.

[Patient]

I used Navionics a bit when chartering in the BVI on my iPhone.

I never used it as a primary means of navigating, however there were a couple times I used it to scan through options when trying to find a suitable replacement place to land.

Example: Ran out of cash and used it to not only search the closest ATM around, but also what the general options were for me to make port. The refresh rate was quite fast, so I could browse the coast of Tortola by swiping my fingers from the cockpit.

Word of warning:
With AT&T I called a month ahead of my chartering trip and spoke at length with someone about what I was planning on doing and what changes I needed to make to my rate plan for data and voice so I wouldn't get hammered with fees. So after a ton of changes and an international call and data plan I went ahead and used it carefully in the BVI.

1 month later my bill was $950. Not joking.
I had roaming turned off and tried as hard as possible only to use the data when I had a wifi spot, never the less I incurred that amount just talking on the phone with my office a few times and using email.

I got the bill reduced by half, but the lesson here is make sure you really cover your ass when using the iPhone overseas. I would recommend getting a prepaid sim card in that area or exploring other options. The "Maps" app uses a ton of mobile data. So be careful.

[sevent]

There are a bunch of other good sailing apps too. I particularly like the anchor alarm. Works pretty well (once you make sure the phone is in a spot that will ready its GPS well down below) and doesn't use the boat's batteries over night.

[randyrhines]

I have an iPad 4g with wi fi and GPS these are the apps I'm really liking so far.... pocketgrbs for winds. Compass eye for compass, not bad, isailor for navigation seems
Better than Inavx because its simpler and the vector map zooms better. Sail compass and speedometer are nice too.