The new TomTom app that turns an iPhone into a turn-by-turn GPS navigation system spells the beginning of the end for standalone GPS. Not everywhere, but at least on dashboards, where a smartphone can now do everything a GPS can do and cost less than purchasing both.

Like most users, I have been unhappy with the GPS applications available for my iPhone. While overpriced at $99.95, the TomTom software is the first to truly bring standalone GPS performance to a smartphone platform. When the company releases its car kit, dashboard mounting and powering the iPhone will become easier.

With iPhones selling for as little as $99, the combination of phone, software, and mounting kit should cost less that $300. While you can purchase a nice GPS for that, it would provide little more than navigation and perhaps hands-free for a Bluetooth phone. The iPhone is a real pocket-sized computer that does everything the GPS does, and a lot more besides.

Still, a standalone GPS can--and this may be the genre's salvation--provide a larger, more readable screen than the iPhone. It can also provide real (not touch screen) buttons for some functions.

For people who can afford both, an iPhone and separate GPS may still offer benefits in ease-of-use, provided GPS manufacturers focus on meeting the smartphone threat.

In my car, I am still using a Garmin Nuvi GPS, which provides navigation and a Bluetooth speakerphone for the iPhone. My guess is I will continue to use that even when a TomTom car kit appears.

However, because the iPhone will have a live, interactive connection back to TomTom, there are many features the company can add to its platform that traditional GPS users, even those with FM subcarrier "traffic" receivers, will find hard to match.

TomTom is already offering a feature that uses information from other users to create better routing. Over time, location-based features should make smartphones or other two-way devices the best option for navigation in all but wilderness conditions or in aviation.

As those services roll out and as my standalone GPS units--I have two or three--become outdated or are stolen, I will probably more to whatever TomTom or its competitors are offering.

What will it take to keep me with a standalone device?

First, I need to be able to program it by speaking by destination. It needs to be perfect and quick. Second, I do want a larger navigation screen than what my iPhone can offer. Third, the GPS needs to tether to the phone to get traffic, weather, and other updates while I drive.

Give me those things, and it will still be possible to see me a GPS for my car. Otherwise, my smartphone will suffice.

Industry veteran David Coursey tweets as @techinciter and can by contacted via his Web page.