On Mon, Aug 29, 2011 at 08:07:04AM +0200, michael lohr wrote:
My feeling with the problem of flooded tiles always was that the geofabrik extracts are to blame - they're too "tight" in some places, so the coastline breaks in the extraction process already, not during the splitting. That happens for instance in the northwest of germany around emden and in the northwest of india in gujarat.
The Geofabrik cutting polycons are not set in stone. A long time ago, I took a couple of iterations with Frederik Ramm to get a good extract of Finland that would include all of the country border, plus some lake multipolygons in the neighbour countries. I did this in Osmosis and JOSM by extracting the country borders from the Geofabrik extract and by downloading some data in JOSM, and finally editing the cutting polygon in a separate JOSM layer. It still takes a little tweaking to get the coastlines right. I have manually chosen the tile borders so that the coastline will end outside the tile border. Only in the Swedish/Finnish border I am using extend-sea-sectors to make up some coastline in Sweden. 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. Best regards, Marko