my new iPhone has GPS, now what do I do?

UPDATE: Steve Jobs confirms GPS on iPhone 3G.

image via Engadget
ENDUPDATE

Assuming Steve Jobs announces the 3G iPhone with built-in GPS at WWDC.  (Based various rumours and software builds.)

A few uses of GPS information:

• You can embed your location into photos that you take (geocoding or geotagging photos).  Many applications and photo web sites can read this information and display your photos on a map.
• You can track your position for later display, this can be used to measure sports performance or to record a vacation.  (You may need to use conversion software to get the track into a format your desired map can display.)
• With communications software, you can find proximity information - this may be the locations of all of your friends, or how close you are to the nearest coffee shop.
• You can get driving or walking turn-by-turn directions (often this is a pay service) as well as just seeing your position on a map (usually free).

Although I don't have an iPhone, I have used my GPS loggers and Nokia N82 mainly for the first two applications.  As far as I know, the Nokia series of cellphones are the first mainstream ones to support in-camera photo geocoding.  Some sites that support using GPS information include:

Photo Sites

• Flickr (if you enable GPS-EXIF) - see http://flickr.com/map for everyone's images
• SmugMug
• Picasa Web Albums
• PBase - see maps.pbase.com for all of your images
• Panoramio - see http://www.panoramio.com/map/ for everyone's images

Travel / Sports Sites

• EveryTrail
• Mountain Bike Guru - MTBGuru.com
• Nokia Sports Tracker

GPS Data Conversion Sites and Software

• gpsvisualizer.com
• gpsbabel.org

Please feel free to share any sites, applications or uses you find for your iPhone GPS.

Background Information

A GPS is a device that can use satellite signals to calculate your position on the earth.  Its ability to do so depends in part on the size and sophistication of the GPS sensor, and also on how many satellites it is getting a clear "in view" signal from.  Anything that blocks the GPS view of the sky (a ceiling, tall buildings) will interfere with the ability to get a good position.  In general, GPS will not work at all indoors.  As a simple rule: the more of the sky you can see, the more satellites your GPS can see.  (Note: Although this is sometimes referred to as a "clear sky view", clouds and weather have little impact on GPS.)

Because it is an active signal reception and calculation device, GPS can represent a substantial part of the energy use of a cellphone - you probably want to disable it when not in use.

GPS is also associated a lot with navigation technologies, but this is just software on top of the basic GPS information.  As route calculation is quite compute-intensive, often this is done off-device, as in Google Maps, which requires an Internet data connection at all times.

WARNING

Not all applications are GPS-data aware.  Some photo applications may damage (remove or alter) your GPS-EXIF information.

UPDATE - Official Apple Pages

Apple's documentation confirms in-device photo geocoding and provides more information on other features.

In addition to A-GPS, iPhone 3G uses signals from GPS satellites, Wi-Fi hot spots, and cellular towers to get the most accurate location fast. If GPS is available, iPhone displays a blue GPS indicator. But if you’re inside — without a clear line of sight to a GPS satellite — iPhone finds you via Wi-Fi. If you’re not in range of a Wi-Fi hot spot, iPhone finds you using cellular towers.

...

Take a photo with the camera, for example, and iPhone can geotag it with GPS location information.

...

GPS on iPhone is active only when you need it. iPhone powers the GPS unit on and off quickly and automatically

Apple Canada - http://www.apple.com/ca/iphone/features/gps.html

For info about mapping, see http://www.apple.com/ca/iphone/features/maps.html

The camera is still only two megapixels, which is not surprising given the thinness of the device.  Get all the other tech details about the iPhone 3G at http://www.apple.com/ca/iphone/specs.html

Comments

[Owen Stephens]

But what does GPS add over the current 'triangulation' service already available. Clearly a slightly more accurate location, but in terms of Geotagging photos, how accurate is really important? For location based services like 'show me the nearest', the triangulation would seem good enough as well.

It just seems to me that the important thing here is not GPS, but the ability of other applications to access location data from the device (GPS or triangulated) - and presumably those who have the software development kit for iPhone already know whether this is possible or not?

[Richard Akerman]

There are two other techniques for location determination:
1. Use cellphone tower information
2. Use wifi node information

If I understood Steve correctly, Google Maps on the current iPhone mainly uses wifi node info.

Both of these have a huge disadvantage in that they require you to gather tremendous amounts of information in advance, and they don't handle changes well. Presumably they were able to gather enough info to cover most of metro US acceptably, but I don't see how this can possibly scale to covering the entire world. GPS gives you a much more accurate location anywhere in the world it can see enough satellites, with zero information update or maintenance cost.

Because of that, I think that Location Services will get a much bigger push if the iPhone has GPS. I don't know how reliably you could do road nav using just celltower locations, for example.

[glen wood]

@Richard Akerman

you can't do road nav by celltower triangulation - at least not anywhere I have tried, throughout the Midlands in the UK. In my city, the iphone is usually inaccurate by 0.5 to 1 mile from my actual position.

but then the iphone is very US-centric (and probably very metro-centric within that). It misses lots of features that every phone user in Europe takes for granted (my friends almost refuse to believe me when I tell them some of the stuff thats wrong/missing with the iphone) and includes features that seem useless. I guess it's aimed at bay-area or NYC hipsters, and the rest of us have to like it or lump it.

@owen

i like my photos to be geotagged to within a couple of yards accuracy - 10ysrds min. Recording the heading would be good too :)