basic iphone gps question

[plaz]

Greetings all. I have recently bought an I phone 4 for work (truly). I have never previously used a gps, and am a bit of a luddite. I think this is a basic question, but I don't understand how to make the phone tell me my position as a grid reference that will relate to my topo maps. This is all I want, really, although I am sure the waypoints etc would be useful too. I have downloaded an app called cyclometer that tracks rides and runs giving time/distance data and maps it on to google maps, which is quite fun, but this will not be useful out of mobile phone range,as the maps need to accessed each time. Does the motion-x app that you guys are talking about in the other thread give you a grid reference? I looked it up and it seems to use open source maps which sounds like a wonderful project, but I still use paper CMA maps for most of my trips, having developed a collection over the years that cover most areas I walk in. Any other useful bushwalking iphone suggestions welcome too- there seem to be a gazilllion camera apps and photo organisers - has anyone found any particularly useful? Thanks in advance, adrian.

[frenchy_84]

The formula you need is called redfearns formula which transfers grid coordinates to geogrpahic coordinates and vice versa (http://www.ga.gov.au/geodesy/datums/red ... o_grid.jsp) whether motionx can do it im not sure as mine currently doesnt want to load (typical rubbish iphone 3g).

[flatfoot]

Motion-X will display UTM (I.e grid) co-Ordinates. It seems that it only supports the WGS84 datum (someone correct me if I am wrong).

I also check out the following app BitMap ( http://nixanz.com/iphone/55-bitmap ). It allows you to load digital copies of standard topo maps into the iPhone. This is easiest if you buy the digital images from your relevant mapping authority. There is a bit of a conversion process required to load the maps in.

The maps that Motion-X uses are not generally good enough for bushwalking.

[sthughes]

If you dont already have digital maps to use with Bit Map, another good app is Memory Map. You can purchase the maps for a reasonable price in the app and they download straight to your phone on the fly. But remeber to download the maps of were you are going first in case there is no data coverage there. It also spits out UTM co-ordinates, so it is useful without any maps too.

[bmak]

Mud maps is also a good one.
Only $3 per area map too

[Son of a Beach]

There are so many iPhone GPS apps it's crazy - both with and without mapping. If you want to see your current location as either coordinates or grid references, the main thing is to make sure that the app you choose will display your location using the same datum as your map(s).

For Australia, the two common datums are GDA94 (which is almost identical to WGS84), and AGD66. AGD66 is used by most older maps, including many of the current Tasmap publications. These are generally being phased out and replaced with maps which use the more recent GDA94. The iPhone's internal location APIs does everything in WGS84, and most apps include no conversion to any other datums. So if you are likely to use maps with a datum other than WGS84 or GDA94, then be very careful to make sure the app you use can display coordinates or grid references in other datums.

[frenchy_84]

AGD66 is used by most older maps, including many of the current Tasmap publications.

Tasmap must be waiting for an upgrade to Windows 95 before changing datums!

For all intensive purposes GDA94 and WGS84 are the same, GDA94 uses the GRS80 ellipsoid which is near enough identical to the WGS84 elliposid. however GDA94 assumes the Australian Continental plate doesnt move and is fixed in time as of 1994, perfect for nearly all Australian purposes as there is close to no shift from different areas on the continent (unlike NZ), while WGS84 is the default GPS datum and therefore relies on global accuracy so the continents are stationary within it and there for WGS84 coordinates should be specified with the epoch they are taken. As the continent is moving approx 7cm a year in a NNE direction, WGS84 and GDA94 are diverging by that each year. Which is why there will be a new realisation of GDA in the next couple of years.

The difference from AGD66 to GDA94 is approx 206m NE (?)

What does this mean for you using an iphone GPS?.... Nothing, the best accuracy that you could ever hope to realisticaly achieve is 20m. As flat foot says Motion X can pump out UTM coordinates (the Grid realisation of WGS84) they can be used as MGA coordinates (the grid realisation of GDA94)

[plaz]

Thanks, guys, that's been very helpful. It really is astonishing to me what this little device is capable of. Haven't been as entranced by a new toy since I got an electric train set at the age of 6. Now all I need is someone to write an augmented reality application so that I can point the phone at a patch of scrub and it will tell me where the line of least resistance is...
Cheers, adrian

[Nuts]

Ive been hearing of an app that allows you to scan barcodes in store and compare online prices for gear from a linked price finder website

[tastrax]

They are amazing devices - my family were in a restaurant and I wanted to know the name of the song playing over the speakers - Son pulls out the iphone, records a few bars and then promptly gets an answer. Truly amazing! Cant remember the name of the app.

[andrewbish]

It's called Shazam

[Liamy77]

i need more pocket-money!!!

[andrewbish]

While on the topic of handy iPhone apps for the outdoors, here are my favs:

Motion-X - for GPS, navigation, tracking, WayPoints, etc
pUniverse - Helps you identify stars, planets, etc (more for fun than navigation)
APOD - Astronomy Picture of the Day (very cool if you're into that sort of thing)
Evernote - Enter notes, ideas, voice memos and will synchronise to another computer with Evernote installed ie. your laptop
TapTalk - Read and make posts to forums - like this one! (listed as 'Bushwalk Tasmania')
Stanza - Download and read e-books - many of them are free and the others are generally cheaper than the print versions.
SASSurvival - Electronic version of the SAS Survival Guide
Fieldrunners - Ok, it's just a diverting game

[Nuts]

The (or maybe just my) mind boggles
I saw an intro for an app that can translate written language instantly via the camera... I believe they only had spannish/english but the rest wouldn't be far off...

[Liamy77]

The (or maybe just my) mind boggles
I saw an intro for an app that can translate written language instantly via the camera... I believe they only had spannish/english but the rest wouldn't be far off...

they tried US english first but the us education system couldnt get it to spell properly!

[Son of a Beach]

The (or maybe just my) mind boggles
I saw an intro for an app that can translate written language instantly via the camera... I believe they only had spannish/english but the rest wouldn't be far off...

Yes, "Word Lens" is very cool, the way it displays the sign, page, whatever on the screen, with the translation in place of the actual words. It is free to try out (only the language packs cost money), and the free version simply reverses the spelling of all words (just as a demo).

However, It is nowhere near as good as shown in their promotional video. It is good enough to provide a useful translation if the text is in clear large letters, but even then, the translation of each word can come and go, to some extent, and some words only get partially translated.

A very remarkable concept, though, and very well executed.

[bmak]

My favorite gps app is gps kit.
Been using it for awhile and the latest update is great.