iPhone GPS Receptions

[IceProwler]

I have been marking my spots this year using my iPhone rather than my regular GPS unit. Does anybody know how accurate the iPhone GPS is, or have experience with it? I am afraid I may not be able to find some pretty precise structures I have marked.

[Colt_45]

I "drop pins" and bookmark them if that is what you are doing through your "maps" app. I can drop a pin at my house and it actually shows up on the wrong side of the road, but the right distance from the road. I live in the county with a pretty good length driveway too. So I can't say it is pretty close. My neighbor even has a cell tower in his back yard too.

My navionics app runs better than the maps. Paid 15 plus tax...there is the smartphone thread on here too.

Sorry I can't be too much help

Colt

[Crm7290]

The iphones gps is a-gps, meaning assisted GPS. it is assisted by cell towers. Anywhere with 3g will have better gps readings. Stick with the real gps

[IceProwler]

Do you know if that is true with the iPhone 4 as well? From some info I was able to find on the web it sounds like the 4 is much more accurate than the 3. Also, I downloaded the Motion X ap to check on the accuracy and it stated that the GPS is accurate within 16 feet. Hopefully it was that accurate while marking structure.

[Crm7290]

"The iPhone 3G, iPhone 3GS, and iPhone 4 use A-GPS -- or "Assisted GPS" -- which in basic terms accesses an intermediary server when it is not possible to connect directly via satellite -- indoors, for example -- and this server provides the nearest satellite with additional information to make it possible to more accurately determine a users position." This was found when googling that question.

I have motion x lite, it was recommended to me by a geologist at Winona. I havent tried to use it yet. Im going to put it back on my phone right now

[fisherman-andy]

Maps and Motion X is GPS assisted meaning they need to download or cache their maps before use. If you have no cell coverage or 3G service it wont load any new maps for you.

Get the Navionics Lakes North App for you iPhone. That is a standalone and does not really need data assistance unless set with certain preferences that requires it.

[Crm7290]

While Maps and motion x do download the map, that isn't the only thing that the a-gps uses wireless for. It basically acts as a crutch that lets the satellite be found more easily.

Have you seen your phone when it just gives a big blue ring, then other times it gives a full out 3-d blue dot (Perfecty circle water dot I guess you could say)? When it is all blue ring it means it is just triangulating to find you, but when it gives the 3-d blue dot it means that it has connected fully. Once it finds where you are it downloads the correct map at that point.

If you have below 3 or 4 bars when you are on Edge network then you will not be able to get that blue dot.

[fisherman-andy]

You dont really need the assisted GPS, however cellular and wifi triangulation does help locate you faster. However if the GPS does not locate properly due to interference it relies the assisted wifi/cellular triangulation.

Cellular and wifi location services is not accurate and you'll really be off without actual GPS. This would be the case if your using an iPod Touch with a Cellular Mifi or air card.

I never had the Navionics App not able to locate me on my iPhone using just the GPS and no GPS assist with the cellular data/wifi. Same thing goes for me Tom Tom GPS App. No data connectivity required. Remember the iPhone 3G or newer models have actual an GPS chip. An original iPhone only has the cellular/wifi triangulation which is inaccurate.

[IceProwler]

Thanks for all the responses everybody. The thing I still do not understand ishow accurate do you think saving fishing spots on the iphone GPS is? I am using the Navionics Ap.

The points I have saved have been in two situations.

1) When there was no 3G, EDGE, or any other phone signal available; and

2) When there was a strong EDGE signal available

Are marking spots accurate in these situations? One situation more accurate than the other?

[Crm7290]

Do the Tom Tom apps and the Navionics app actually store the maps onto your drive? One of the reasons i dont use my phone as a gps is because I dont usually have service on my drive to and from Winona and didn't think the phone. Maybe things have changed with iOS 4, but I know the maps app does not have anything on the phone. Neither does google earth outside of the globe.

[IceProwler]

Yes, they do store the maps right on your phone. I have even used them in the BWCA.

[DTro]

Not sure about the IPhone, but my DroidX claims an accuracy of +/- 12ft.

[Crm7290]

Well if its how Andy thinks accuracy is on the GPS unit not on the signal so it should matter.

Go stand on a drain cover somewhere and then the next day navigate yourself to that same drain cover. When it says you arrived at the location stop immediately. Do this a few times in a few places to see how accurate it really is.

[fisherman-andy]

Well if its how Andy thinks accuracy is on the GPS unit not on the signal so it should matter.

Go stand on a drain cover somewhere and then the next day navigate yourself to that same drain cover. When it says you arrived at the location stop immediately. Do this a few times in a few places to see how accurate it really is.

I would recommend doing that also. You should get good reception if having clear sky and no interference. But you may end up with varying results depending on the situation. Either way it should be close. But I wouldn't say pin point accuracy.

[Shack]

LOL with no cell coverage, bars or data on a 3G I took some images of a nice fish caught last spring with location services turned on. Posted them on here and a little birdie was kind enough and sent me a map with a pin dropped with in feet of where it was caught. Accurate enough for me and anyone else who bothered to check.

[Hardyboy]

Im using the navionics app and My Tracks app on an android and it has proven to be accurate to within about 6 to 12 feet.

[Crm7290]

Exactly. 6 to 10 feet now isnt the most accurate but for a cell phone it is amazing!

Shack, its called exif data. It will tell you everything about the photo taken unless you deliberately change it yourself. From iphone images I can tell location, amount of zoom, exposure time (depending on the camera) and many other things.

And andy, if it were me doing that experiment, I would do a ton of different measurements and then add up the difference and average it.

Honestly speaking six to twelve feet with fishing can mean the difference between catching a limit and not catching any fish. I tend to just hole hop around an area. Next time I fish I will be trying out motion x gps. Next time after that I will be trying the navionics app

[CaptainMusky]

Exactly. 6 to 10 feet now isnt the most accurate but for a cell phone it is amazing!

6 to 10 feet is about how accurate a normal hand held GPS is. The only real way you can get better than that is if you get a Trimble or something like that and they are nearly $3000. Remember they advertise accuracy in meters and nearly every handheld GPS I have seen advertises 3 meters well, that is around 9 feet. With WAAS you can get less than 3 meters.

In all honesty, if you cant find the "spot" and its 6 to 10 feet away something is wrong. I mean, people never used to have depth finders OR GPS and those old codgers caught fish.