Hi Guys,
I've got a vector mapping application working in C for the Sony Playstation Portable.
It uses Garmin map data, and there are plenty of free compatible map sources available.

Here is a YouTube video of it drawing to the screen:
http://www.youtube.com/watch?v=ZvhbknIGrpM

My question is, every time the GPS location changes, a GPS program needs to
update the map shown on the screen to represent the new location.
But unlike software in commercial GPS units , my program will take the same time
again to draw the screen again like in the video so most of the time is spent drawing/
searching the map file, and there is never a complete map on the screen.

What is the way commercial GPS software updates the screen so fast once the
map is initially drawn?

I have a commercial unit with an extremely slow CPU that draws faster than this.

Cheers, Art.

 

Wow, I didn't think it would be that hard.
It looks like the solution is an R-Tree index.