An easy check is to display the map in MapSource and choose one tile, so this tile will be highlighted.Hi all,
>
> 11000004: 1800192,1406976 to 1968128,1681408
>
> In this tile (north-western Turkey) there are missing two ferry-routes
> (Yalta-Istanbul and Sivastopol-Istanbul). As I opened the tile in josm,
> I discovered also, that there are several objects in that tile, which
> shouldn't be in it. Eg. boundary of USA, Russia
reg. the ferry-routes:
I can't say for sure, but I'd say these ferry lines really don't cross the tile.
I think it is a good idea to write the tile bordes in gpx format, this will help
to answer such questions.
Ah..thats logical. Russia is crossing 180°/-180°reg. "objects that shouldn't be in it":
I would accept Russia for now, but USA really sounds strange.
I think the reason is the very simple that is used now:
For a multipolygon (or boundary), splitter simply calculates the bounding box
of all ways. The result is a rectangle. Every tile that intersects this rectangle contain the
complete relation.
The advantage of this method is that splitter doesn't have to calculate the real MP (which
invvolves many special cases like incomplete data, holes etc). I wanted to leave this
to mkgmap.
I think, this would be acceptable. Splitter would save data with overlap=0, so there shouldn't be a real problem, if these to boundaries were copied to a lot of tiles.For most boundaries, this simple alg. works quite well, because the bbox of the boundary doesn't
contain too much other stuff.
The bbox for Russia is obviously very big and contains a large area which doesn't belong
to Russia. A real problem is USA (and probably other countries with external territories:
Because of Hawai and some other islands the bbox for USA covers almost half of the planet.
I hope I can find an alternative algorithm that is still simple and fast, but doesn't
make this error.