northerntier

I'm about to go on a month-long tour and don't want the thing constantly updating a track; the battery drain would be too much.

I'd love an app that could wake up every 15-20 minutes and take a snapshot.

??

Thanks,
pete

Juha

The "snapshot" can take several minutes. If you move for 15-20 minutes with the GPS turned off (this seems to be what you want), the receiver has to start searching for satellites again. That time can be reduced with wifi / GSM cell tower triangulation, not sure how much iPhone makes use of those.

Burton

Last time I checked the iPhone recorded GPS coordinates as part of the EXIF tag when you take a photo. All you'd have to do is take a shot yourself every half hour or so. You were planning on taking pictures anyway, right?

In any case - you'll need to be in an area that gets a signal from your provider to make anything like that work - which isn't always as seemless as they'd like to make it look on their coverage claims.

northerntier

In only takes 10-20 seconds to get a decent read, assuming good signals.

There's actually an old app called 'HereIAm' that can fire off an email to a preset address at the touch of a few buttons. It's easy, just not something I want to do every 20 minutes.

If I can't find an actual app I'll probably go w/ a combination of HereIAm and the pictures.

cplager

Why do you need to have signal to get a GPS reading?

northerntier

Sorry, I was talking about GPS signals.

cplager

I don't know how smart the initialization sequence is, but if the phone was locked 20 minutes ago and you are moving a biking speeds, my guess is the subsequent triangulations would be much faster.

Another thought for the OP is to buy an external battery to plug into the iPhone and just record your GPS track regularly. If you can recharge at night, then you should be golden. (If not...)

Burton

Because 3G iPhones don't use direct GPS - they use A-GPS; short for 'assisted GPS'. That makes them dependent on alternate sources like WiFi and cellular networks.

njkayaker

^^^

They use those other things. They are not dependent on them.

keithm0

https://trackmytour.com/

It doesn't automatically record every 10-20 minutes, but it only enables GPS & location services whenever you want to record a waypoint. I've played around with it a bit, and it does seem to greatly extend battery life.

Burton

Since battery life was specifically stated to be concern in the original post, I'd think the extended time required to get a pure GPS fix vs the near instantaneous time using A-GPS wiuld make that dependent enough that using pure GPS would be inconvenient at best and useless at worst.

I know its tough, but I'd really like to see you post something constructive ocassionally yourself instead of just nitpicking other poster's comments.

There are some applications available to address that iPhone shortcoming - why don't you try listing a few?

njkayaker

Don't say things that are wrong and people won't comment about it (don't post anything if you are so sensitive about it).

Pointing out that you were wrong about phones being "dependent" is useful to people because you are misleading them into thinking that phones can't be used for positioning without it. That's an important point. Not "nitpicking".

No one was actually talking about turning the assisted-stuff off, anyway (that's "nitpicking"!).

So, you know about applications but are refusing to list them yourself? It's funny because you are criticising other people for not doing something that you didn't do yourself.

njkayaker

The iPhone with these locates much faster than a GPS without them. They work fairly-well to locate even without a gps signal.

northerntier

Okay, I think I'll go ahead w/ using IAmHere, supplemented with pictures I upload from the phone.

Thanks,
pete

Burton

If you had bothered to look at my original post - which was a suggestion that the GPS co-ordinates could be extracted from the EXIF data while taking pictures - all this would have made a lot more sense. But thats not what you're apparently all about. As some people have suggested on some other forums you frequent - don't give up your day job.

njkayaker

^^^
Your suggestion to taken a picture every half hour doesn't make any sense.

And your other post is still wrong.

Burton

Well since you had a whole week to add something constructive to the thread and didn't - thanks for nothing - again!

I've used iPhones for traveling (or tried to) with mixed results. The first generation iPhones has no GPS capabilities. Zip, nada, nothing. But they did allow some navigation referencing by trilateration using cell tower and Wi-Fi network locations. It was entirely dependent on signal reception of my service provider.

Then there was the 3G versions, which were designed to work optimally on A-GPS. Mostly because this is an iPhone and not an iGPS unit. Which means its primary function is as a phone which is normally used intermintantly in populated areas where there are lots of metal structures, and lots of signal towers. A lousy environment for GPS reception but ideal for A-GPS.

And as long as there's good reception - Google Maps and a number of other Internet services completely negated any need for any pure GPS functionality for me. And signal strength was usually reasonable along most highways and around populated areas. So can you go pure GPS? Sure - except that A-GPS gets a fix faster anyway, and if you're in a 'no reception' area, you might still get a GPS signal, but thats pretty useless without something to reference it against or a way to store the information.

Which is pretty much what most GPS applications do. They let you download maps and other references so that you have something to plot co-ordinates against. Except for some of the better packages. For some reason those include their own GPS antenna, a protective case and an additional battery pack.

Maybe because there's five or six different kinds of GPS antennas and the one for the iPhone was picked for small size - not stand-alone performance. As mentioned - this is an iPhone - not an iGPS unit and its EXPECTED to be used with A-GPS.

Then there's the other little note that all those GPS applications for iPhones include at the bottom of the page:
Yeah - most people using GPS applications on an iPhone find they run out of juice pretty quick - maybe after 4 or five hours. With some judicious planning and by shutting down as much as possibe, its possible to get 10 to 12 hours, and that can be stretched using an auxiliary battery pack, but I've always had to have access to an electrical source ON A DAILY BASIS when using any GPS application. Which is fine for people that travel by car or just do day trips or check into someplace with an electrical outlet every night. But I think this post included some pretty specific comments:

So personally I think even attempting to use pure GPS on a 30 day tour would be a very frustrating experience. Without the assistance provided by A-GPS it could take up to 15 minutes to get an accurate fix, and so uploading a data point every half hour wouldn't necessarily be a radical departure from having the phone on continuously. And yeah - accurate fixs are so much of an issue that there are even applications out to tell you the accuracy of the GPS reading. I'm using GPS Status myself on an iPhone 4. Cause just because you get a reading doesn't make it accurate - you may have to wait longer to get a waypoint accurate to within a few meters instead of a few kilometers - or somewhere in the next county.

So on my last trip I just took pictures and used the time, date, and GPS positioning referenced in the EXIF data of the photos to plot my own maps when I got back. Still needed an external battery pack and still needed to watch battery management, but a lot less so. I also had photos to reference or insert and not just waypoints, and a lot less hassle. Not that I think you'd undertand all that - but a few other people here might.

Don't give up your day job.

njkayaker

And your earlier post was still wrong and misleading.

Why are you talking about ancient phones? That's not very useful.

You are pointing out the obvious. That's not very useful either.

WE KNOW THAT A-GPS IS FASTER. Why do you keep repeating stuff that everybody already knows? It is still not "dependent" on it.

???? You keeping saying not to use the phone GPS and then you recommend using the phone GPS (in photos). You aren't making sense!

Winnershcyclist

I use a XPAL 18000 battery https://www.youtube.com/watch?v=rNhPGcnOfkk for days upon days use and a smaller version that gives me an extra 4 hours on my Android smartphone and Iphone this also gives me apps like Endomondo, Track Me Micoach etc to record the routes and also have a Zepyr HXM HRM plus Google maps Sat Nav now that it supports Cycle routes. this video was when i used to have a standard Sat Nav and BB but still went upto 5 days use

Juha

It could but it seldom takes that long. It takes about 12-13 minutes for an unassisted GPS receiver to download GPS almanac and other required info from the satellite. If the last downloaded almanac is relatively recent, and the location hasn't changed a lot since then, getting a first fix is a matter of a couple of minutes or under a minute.

You are describing an assisted GPS. Pure GPS devices (unassisted), or even GPS chips in smartphones don't work like that. GPS readings are accurate in the sense that the (unassisted) receiver doesn't report a "fuzzy" location at first and work its way from there. If there's enough info to calculate a GPS fix, it's done to the GPS specs, no reservations. A pure GPS receiver has no way of telling if a calculated result is accurate or not, as it lacks independent reference data. Devices with GSM/wi-fi have access to such data.

Regarding power consumption: GPS alone is a power hog. From what I've read, GPS receivers in smartphones often use longer intervals in between fixes for this reason. If you use assisted GPS with all bells and whistles, you have a lot of power hungry technologies enabled simultaneously (GPS, GSM, wi-fi and a high resolution colour screen). Whether that consumes more batteries than running an unassisted GPS alone depends on many factors.

Finally, and as a side note, I hope we all can discuss GPS without resorting to personal attacks. If not, the thread will be closed. Thank you.

--Juha, a Forum Mod

lhendrick

iPhone with GPS does not need a phone provider signal to work. Period.

njkayaker

* Continous tracking on smart phone is easy but it takes too much battery power (we all know this). There are many apps that do tracking (it doesn't appear too hard to do).

* You could use an external battery pack to deal with this. There are lots of these and they aren't that expensive. If you had access to power nightly, you could run the phone continuously with a battery pack large enough. It takes some time to charge the phone this way (and you'd want to take care the system doesn't get wet).

* Dedicated GPS units will do tracking but they can have battery issues too (still better than phones). The Garmin bicycle/running units might be good choices here. Turning the screen off helps alot here. There might not be an easy way of dealing with the data while you are touring.

* Apple doesn't allow for periodic tracking (it appears). Jail breaking might provide access to apps that will do that for you.

* Using a manual process for taking your location (like using pictures) seems too inconvenient. If A-GPS is availiable, it would help here (or for any automated peroidic tracking), as Burton was hinting at. That benefit won't be available if you are out of cell-phone range but that isn't really going to be that much worse than turning a GPS unit on/off to conserve battery.

* Another approach is to get an external Bluetooth GPS receiver. These appear to have good battery life (around 12h) and cost about $100. The GPS antennas these use should be better than what is used in phones. It appears you'd have to jail break the iPhone to use these. It's possible that these have memory so that you wouldn't need to keep the phone on all the time to get the data. Ideally, the unit would support BT 4.0 LE (which uses less power).

* Android might be a better choice for this than iOS.

* If you were really hot on doing this and didn't mind spending money, you could get a generator hub ($220 for a wheel with the Shimano generator hub and about $400 for the Schmidt Son hub). And $100-150 for a USB charger (B&L has a light that has a USB charging plug). You could use the hub to charge a external battery pack.

* You want to keep an eye on making sure whatever you do is weather proof.

Burton

Gee - sorry if I tried to cover all the bases. The OP didn't specify what model of iPhone he had and not only does that affect things - so does the OS he's running as every app has minimum requirements and some I can't even run on my relatively recent but now discontinued iPhone 4.

Regardless - if I was going on a 30 day bicycle trip and thought I needed GPS - I'd buy a dedicated GPS unit. An iPhone has a digital camera built in too but a dedicated digital camera still does a much better job.

Burton

Maybe I've been doing something really dumb, but aside from pulling the SIM card - the only way I've ended up with a choice between A-GPS and pure GPS is by running out of reception.

And of course I'm Canadian and things are a little different here, but roaming charges are something I really like to try to avoid myself. And the best way I've found to do that is to yank the SIM card. Which disables A-GPS and puts me at a serious disadvantage anytime I'm near tall buildings, trees or anything else which interferes with line-of-sight performance.

And the only way I've managed to conserve a battery to any extent is to turn off the phone - which seems to re-initiate a GPS calibration from zero.

Or did I miss something?

northerntier

My phone is an iphone 5. To Burton, most US contracts include free roaming at least in the US, so that's not an issue.

I've used Schmidt SON generator hubs and I don't like them on tour, because you get nothing (or sometimes less) on those long uphills. I have two good batteries I'll take (one 8000 mAh, the other 10000) to charge my phone and ipad mini (and maybe kindle). Ironically, this tour is southern east coast, so it'll be flat and would have been ideal for the generator hub.

The iphone does everything I need. I use MotionX to track my route. I also have the entire planned (ACA) route loaded, the 120 ACA-mentioned campgrounds loaded as waypoints, and I've cached about 2.5 GB of tileset data so I won't have to exhaust my monthly data allowance.

MotionX will even do exactly what I want: send an email w/ GPS fix each hour. The problem is that either the GPS is on that whole hour, or the emails are only sent when the phone is unlocked and the app is in the foreground.

Except for the battery issue I see no reason to have a dedicated unit. Instead, I use at least as much space/weight for the batteries :-). W/ the two batteries I'm taking I should have to plug in more than every three or four days, minimum, even if the phone is on all the time. State parks, and sadly a few RV parks, so plenty of power.