On Mon, Aug 29, 2011 at 10:08:26AM +0300, Bartosz Fabianowski wrote:
This is why I collected the coastlines for all of Europe in a single file. When all European coastlines are available, you no longer have to tweak tile boundaries.
There are a few drawbacks to that approach. First, you will have to download and process much more data than just the country extract. Second, if the continent extract was generated at a different time than the country extract and there have been edits to the coastline, your map might not correspond to any snapshot of the OSM database.
I think that it could be useful to have the tile-splitter support a set of fixed tiles that it would split itself further as needed.
I presume you would then use this so that you extract a larger region and then let the splitter generate tiles for a subset of this region?
Right, the idea is to make the combined bounding box of the splitter-generated tiles something else than a rectangle. If we ensure that all coastlines that were "cut open" in the Geofabrik extract will have their endpoints outside the splitter-generated coastline, the flooding should be gone.
With a sufficient margin of safety between the two regions, this should work by providing the splitter with coastline data even when tiles grow due to rounding.
Right. I wonder if Geofabrik or some other entity could start providing a little wider coastline extracts that are in sync with the Geofabrik country extracts. Boundary extracts could be nice too, but I suppose that the Geofabrik country extracts already include all the boundary=administrative lines of the country. Marko