[OSM-talk] negative sea tiles
Lars Aronsson
lars at aronsson.se
Thu Apr 26 11:52:37 BST 2007
I have seen the coastline tiles where a bunch of diagonals cut
through and make everything a mess, apparently caused by the 400
node limit in Frollo. The following is a different problem.
In three places, where a piece of land (island or peninsula) cuts
through the right hand side of a tile, but the rest of the tile is
water, the tile becomes negative. I'll try to draw an ASCII
picture:
+---------+
| |
| ......
| : |
| ......
| |
+---------+
Here, the coastline segments enter top right, go
counter-clockwise, and exit bottom right. The water should be on
the outside (the right side), but instead is drawn on the inside.
I only checked close-areas.pl on one example, and the graph was
closed with a single segment on the right of the tile.
I think I've seen all kinds of combinations of islands being cut
in two by a tile border, but this is the only one where I've seen
this negation happen.
My three examples are:
1. The tile http://dev.openstreetmap.org/~ojw/Tiles/tile.php/12/2190/1266.png
http://informationfreeway.org/?lat=7646904.2239&lon=1395892.708&zoom=12&layers=B000
2. The tile http://dev.openstreetmap.org/~ojw/Tiles/tile.php/12/2189/1269.png
http://informationfreeway.org/?lat=7616721.1589&lon=1385153.30785&zoom=12&layers=B000
3. The tile http://dev.openstreetmap.org/~ojw/Tiles/tile.php/12/1848/1878.png
http://informationfreeway.org/?lat=1659296.90255&lon=-1951169.37965&zoom=12&layers=B000
--
Lars Aronsson (lars at aronsson.se)
Aronsson Datateknik - http://aronsson.se
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