Averaging GPS Co-Ordinates with iPhone

[+bryansmithsemail]

Hello,

 

I am just getting started in the game and am having trouble averaging my GPS coordinates as taken with my iPhone. Can anyone tell me the best way to average the following coordinates? Thanks in advance for your help.

 

[+K13]

It looks like each of the screen shots were at the exact same coordinates - 6* 51'3" N, 81*3'9"E. As they are all the same, there is no averaging needed.

[+niraD]

All those images show the same coordinates:

6° 51' 3" N 81° 3' 9" E

 

But in general, you average coordinates the way you average anything. Add up the values, then divide by the number of values. For example, if your coordinate readings are:

 

N 6° 51.051' E 81° 3.150'

N 6° 51.050' E 81° 3.149'

N 6° 51.050' E 81° 3.152'

N 6° 51.051' E 81° 3.150'

N 6° 51.048' E 81° 3.149'

 

Then you could add the fractional minutes and divide by 5:

 

(.051 + .050 + .050 + .051 + .048) / 5 =

(.250) / 5 = .050

 

(.150 + .149 + .152 + .150 + .149) / 5 =

(.750) / 5 = .150

 

Giving you the averaged coordinates of

N 6° 51.050' E 81° 3.150'

 

which is the same location as shown in your images, but in the decimal-minutes format used on geocaching.com

[+Gitchee-Gummee]

Do you have a geocaching app? If so, it will provide you with the correct coordinate format.

 

The coordinates it (looks to be a iPhone 5) given are in Degree-Minutes-Seconds.

That is fine, but you need to do additional calculations if you want Degree-Decimal Minutes, and it is easier to average in decimals rather than base 60 -- for me, anyway. I have not found that the phone allows you to change coordinate format (maybe you can, I just haven't found it).

 

You current position (in Degree-Decimal Minutes format) is always available in the Official GS geocaching app(s). The Intro-app is free, if you don't have it.

[+bryansmithsemail]

Thanks guys. What threw me off was the first Large number. What does the large number mean?

 

 

Do you have a geocaching app? If so, it will provide you with the correct coordinate format.

 

The coordinates it (looks to be a iPhone 5) given are in Degree-Minutes-Seconds.

That is fine, but you need to do additional calculations if you want Degree-Decimal Minutes, and it is easier to average in decimals rather than base 60 -- for me, anyway. I have not found that the phone allows you to change coordinate format (maybe you can, I just haven't found it).

 

You current position (in Degree-Decimal Minutes format) is always available in the Official GS geocaching app(s). The Intro-app is free, if you don't have it.

[+bryansmithsemail]

It looks like each of the screen shots were at the exact same coordinates - 6* 51'3" N, 81*3'9"E. As they are all the same, there is no averaging needed.

 

How does 3 seconds translate into 0.51? i think i'm missing the conversion equation.

[+K13]

3 seconds = 3/60 of a minute or 0.050 minutes

[+J Grouchy]

Thanks guys. What threw me off was the first Large number. What does the large number mean?

 

 

Do you have a geocaching app? If so, it will provide you with the correct coordinate format.

 

The coordinates it (looks to be a iPhone 5) given are in Degree-Minutes-Seconds.

That is fine, but you need to do additional calculations if you want Degree-Decimal Minutes, and it is easier to average in decimals rather than base 60 -- for me, anyway. I have not found that the phone allows you to change coordinate format (maybe you can, I just haven't found it).

 

You current position (in Degree-Decimal Minutes format) is always available in the Official GS geocaching app(s). The Intro-app is free, if you don't have it.

 

I assume you're referring to the 178, 178, 180...etc....

That's directional bearing. I'm guessing you weren't standing perfectly still, facing the same direction every time you took a reading...

[+Gitchee-Gummee]

How does 3 seconds translate into 0.51? i think i'm missing the conversion equation.

Perhaps you are missing more than you think. 3 seconds "translates" to .051, not 0.51.

I'm not saying that to be rude, but decimal placement is crucial. Perhaps you simply had a typo, perhaps not.

 

All that is done here is converting that last digit -- seconds (1/60^th of a minute) into decimals of a minute (100^th of a minute).

 

Having done that, then averaging becomes quite easy. Most folks' minds work better using base 10 instead of base 60.

You can never exceed 59 seconds, as 60 seconds = (1) minute. You can however, have up to .999 minute.

 

It simply makes for easier averaging in that you are only using those digits to the right of the decimal. Any overage of .999 would equate to one minute.

 

As far as that "first Large number"... I am guessing that you mean the one at the top of the screen. Those are degrees of a compass' directional reading. They have NOTHING whatsoever to do with coordinates (shown at the bottom of the screen), which is the point where you are standing. That compass reading is the direction in which you (or the phone itself) were/was facing.

[+Ben0w]

That compass reading is the direction in which you (or the phone itself) were/was facing.

...where North is 0°, East is 90°, South is 180° and West is 270°. Just add some obvious but maybe - for the thread opener - enlightening facts.

[+WarNinjas]

I have a iphone but don't use it to cache. My Android has a app that will average the coords for you. It also has the right format needed.