I originally got interested in writing my own Google Maps -client when I started using Nokia N900. Quite quickly I got frustrated on the built in Maps app. It was too slow, had strange UI, and worst of all it often failed to find what I was looking for. My previous phones before N900 had nice simple Google Maps -clients.
I decided to write a simple Google Maps-client optimized for searching services. In my work I had gotten familiar with Qt and QtWebkit, so it wasn't a big effort to write a simple client using them. After I got basic functionality working, my role in work changed a bit and I got a lot more busy. I did not have enough time or motivation to really polish what I had done and publish it. In anycase, it already worked for my occasional needs. The screenshot shows what it was about.
Nokia Maps in N9 is a lot better than the maps app N900 had. It's not quick to start, but otherwise I'm pretty happy with it, and I use it a lot. Still, sometimes I want to use Google Maps for finding services, since their database of services and points of interest covers couple of places that Nokia's doesn't. This is why I took my old N900 app's code and decided to port it to Harmattan.
I did a first version before QML was chosen as the main UI framework, so I did it using MeeGo Touch Framework. I basically threw away all the QWidget code and replaced it with MTF. Not a big effort and worked quite nicely too. It was far from complete though and I had to use Scratchbox for development since QtSDK support for Harmattan was nowhere to be seen at that time. History repeated itself and again I got more busy at work so my motivation to work on the app on my spare time disappeared.
Lately I've been working more and more with QML apps, like Helium-browser. I enjoyed working on making QtComponents version of Helium. This was because QtSDK finally supports QtComponents in Qt Simulator. This makes development really quick and easy. Last weekend I remembered my old Maps-client and picked up the MTF-based sources and started to port it to QtComponents.
The app also runs on Nemo Mobile, but I have not yet done the packaging since it is not as useful in Nemo, because GPS does not work in Nemo yet.