[mkgmap-dev] [locator] Simplifying the check line in polygon

Sun May 15 14:00:35 BST 2011

Hi Wanmil

I don't propose spending too much time working on efficiency. First of 
all: a boundary is a boundary. All elements inside should exactly match 
the 'real world' boundary in order to avoid highways to be found in the 
next city. Second: there's still some quality problems in the locator 
(like streets which only can be found by selecting all streets first, 
streets which can't be found selecting the city and then the 
corresponding street). Third: what I did was having a modern computer 
(I5-750 processor), and having the computer processing the map 
generation whilst doing other things like eg drinking a beer/watching a 
football game etc.

Cheers, Johan

On Sun, 15 May 2011 14:31:40 +0200, WanMil wrote:
> Hi all,
>
> I am thinking about how to reduce the processing time of the locator
> branch. One time consuming task is the check if a point, a line or a
> polygon lies inbetween, cuts or lies outside another polygon.
>
> Processing time for this check is directly related to the number of
> nodes that define the polygon. So I have the idea to simplify the
> boundary polygons. By cutting some complex parts of the polygon the
> number of points should be lowered although most of the elements 
> lying
> completely inside the polygons should still lying completely inside.
> The elements that cut the simplified edges must be rechecked with the
> original polygon.
>
> Does anyone know a suitable algorithm for that?
> Any other ideas concerning this problem?
>
> WanMil