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[mkgmap-dev] New locator branch

From Stefan Schunck stefan.florenz.schunck at googlemail.com on Fri Mar 18 14:43:21 GMT 2011


stupid question:
If the polygon points are sorted (i.e that area is always to the left side
of the border; anti clockwise orientation ), then the multi polygon
algorithm could know that solution 4 is incorrect.


2011/3/17 WanMil <wmgcnfg at web.de>

> I have a big problem to continue the development on the locator branch.
> I observed that a lot of admin_level boundaries (2,3,4,5 and sometimes
> 6,7,8,9,10,11) are not useable because they are not completely contained in
> the tile data. The polygons are closed automatically but this is only a good
> guess in which direction they have to be closed. The probability is quite
> high that they are closed in the wrong direction.
> I have attached a picture which visualizes the problem a bit more.
> 1. Red and green are two relations with e.g. admin_level=4. The black
> rectangle shows the tile bounds.
> 2. The splitter does not put the complete relations into the tile. So the
> read boundary is contained partial only.
> 3. The multipolygon algorithm automatically closes the red boundary with
> best guess.
> 4. Now we have two different boundaries with admin_level=4 which cover
> exactly the same area.
> I think this will be a big source of complaints. So before continuing with
> the locator branch I think it will be more worthy that the splitter is able
> to put complete relations to a tile.
> Anyone here who wants to start with that?
> WanMil
>  I have created a new branch for the automatic locator changes.
>> It can be downloaded from http://www.mkgmap.org.uk/snapshots/
>> WanMil
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> mkgmap-dev at lists.mkgmap.org.uk
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