Katharine's work in pushing the boundaries of 2-way app communication inspired me, so I thought I'd try do something myself. Unfortunately, I'm not much of a real coder but I hacked away most of today and finally got somewhere. I was excited, so just thought I'd share where I was at, and maybe I could get some feedback/ideas on where to go next.
This is an app (iOS only, sorry!) that finds your current location, plots you on the standard Apple MapKit map, and then does some bitmap image manipulation on that and sends it to your Pebble. The corresponding watch face just sits there and draws as it comes in at the moment, but I plan to add some smarts to it to talk back/control the phone app. I haven't done much real outside testing as it was raining here tonight, so had to simulate moving locations all in xCode. I'll try get an IPA/pbw combo up at some stage if anyone else wants to play, and source when I've cleaned it up (as I said, it's more of a hack at the moment).
Here's an example image:
(Honolulu is one of the built-in locations in Xcode, the black bit in the corner is the sea).
Some to-do stuff:
Test it outside (hopefully tomorrow)
Try fill the screen (currently 128x128 as that divides nicely)
Swap from the current "always-on" iOS GPS mode to the "significant change" mode (should reduce battery cost for both iPhone and Pebble)
Try clean the code up so it is share-worthy
Work out how to background the app and still keep the phone updating the watch with location data
Implement some control scheme to talk back to the phone and set the zoom level - at the moment I have it about 400m in either way, but I'm sure some locations would work better further away or closer.
Then maybe use the code to build another app (for myself) that plots the location of my morning bus on it in real-time as an map overlay, so I can watch it come down my road and maybe get to work on time...
P.S. A big thanks to Katharine, as a fair bit of this was based on her peaPod - all the large AppMessage transfer stuff and her album artwork image/dithering stuff (even though I've ended up not dithering at the moment, just using a threshold value).