[mkgmap-dev] Overview map: tiny patch/review series

Tue Jun 16 07:55:26 BST 2009

Hi Mark,

Am 16.06.2009 um 08:33 schrieb Mark Burton:

> Recently, Coord.distance() was replaced with a much speedier
> implementation because a lot of cpu cycles were being wasted there.
> The newer function appears to be accurate enough for our purposes.

The DP code contains another distance calculation. What you must  
calculate there is the distance of one point to a line. The  
Coord.distance() is used in that formula, but I do not understand the  
formula itself. Maybe it's some genius trick to simplify the  
calculation, but I do not get it. The only thing I see is that when I  
reduce the error distance the simplified ways look "nicer". But the  
preset error distance of one half of the resolution should be small  
enough already. So my assumption is that the actual error distance is  
much larger than expected, which may be due to a bug in the code.

Regards
Thilo