So: What is "GPS"?

My friend Peter reminds me that I haven't posted this week.

It was busy! Two big dances for the annual Playford English Country Dance Ball which included house guests, a seder, another normal English dance, a trip to SF to see the terrific art work of a fellow alum from Kirkland College, and Easter looming as well.

But part of the problem was: how to talk about this rather complicated and overloaded term "GPS".

Coincidentally, as I was riding in the elevator back to our car in the SF garage, I overheard a conversation that captures what I mean.

"So we're going to go to Helen's now, right? What is Helen's address? Do you have it?"

"Yes, I'll give it to you. Oh, but do you have GPS?"

"Yeah."

"OK, I'll put it into your GPS."

They meant a navigation system that uses GPS, of course, but it's worth spending a little time to tease apart some of the underpinnings.

GPS means Global Position System, which is a space-based navigation system offered by the US government. Using a set of satellites in space, control and monitoring sites on Earth, a GPS receiver is capable of determining your position on the planet, including elevation.

This information can then be used in a wide variety of ways, some of the most useful include combining data with maps for applications such as driving navigation, tracking, letter boxing, and more, more, more.

The iPhone and the DROID both have genuine GPS chips in them, similar to what are found in GPS navigation systems for cars. Different chips sets have varying quality and reliability characteristics.

The iPod Touch does not have true GPS. It is possible to perform a quick and less accurate substitute GPS using the wireless network address. This is sufficient to enable a number of interesting and useful apps, but you will find that there are a number that iTunes will not let you install.

Probably the most common GPS app for most people is car / travel navigation. This combines the now-familiar ability to calculate a travel route from point to point (e.g. using Google Maps on your computer) with turn-by-turn directions with voice prompting, tracking your progress along the route. These are now common integrated add-ons in car purchases and they can be also bought separately and perched on dashboards, powered by the standard old "cigarette lighter" port on the dash.

Both the iPhone and the Droid have the advantage of portability. Navigation no longer has to be restricted to the car.

A huge benefit for the Droid (and general Android platform, I believe), is that a full-featured GPS navigation system, complete with voice prompting, is included for free. I am told that on the day that the Droid was announced, the stock price of GPS navigators such as Tom Tom dropped by a significant percent.

GPS naviation apps for the iPhone are not free (as of this moment) and accessing the system and specific features (such as voice prompting) also require additional yearly fees.

For me this makes the Droid quite compelling, but from a feature comparison perspective, the two are very comparable.

Next Up: Other fun and useful location based services