[mkgmap-dev] New locator branch

Thu Mar 17 21:13:18 GMT 2011

> WanMil schrieb am 17.03.2011 21:12:
>> 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.
>
> Moin,
>
> just as an idea: How about collecting the is_in data of the objects and trying
> to use this data for recovering the missing boundary information?
>
> If you have some is_in data points inside of an area, then the is_in data should
> (mostly) match the boundary data. For an unclosed boundary this could be used
> for guessing, to which side of the boundary it is relating to. And for a
> boundary completely surrounding the tile, this could be used to provide the
> missing information.
>
> Gruss
> Torsten

For admin_level=2 it works. The problem starts with the other levels. 
The assignment between admin_level and is_in:xxx tag is somehow country 
specific.

And another requirement is also hard to achieve: performance. The branch 
is not optimized very well yet. But I am sure that such searches for big 
areas from all items of a tile are quite expensive no matter how 
optimized they are.

WanMil