[OSM-dev] Finding water vs. land
frederik at remote.org
Sat May 9 17:50:56 BST 2009
> This works fine, except for coastlines, where I have two problems:
You're having exactly the same problems as the tiles at home project. The
project has solved them by artificially closing the coastlines to form
an ocean polygon. The mechanism to do it is in close-areas.pl if you
care to have a look.
> * The coastlines are just open lines, but I need closed areas for
Water is always on the right, so the direction of the coastlines is
important for you.
> * When I download data in the middle of the ocean, no coastline crosses
> the tile and I do not know that the current tile must be filled
> completely with water
You need to either download larger areas, or build an index that tells
you which tile is "blue" and which "white".
> * get a complete, closed coast line (possible for the entire world?)
> and both best via some HTTP request :)
A closed coastline for the entire world would probably be between 100 MB
and 1 GB of data. Sure you want that?
Frederik Ramm ## eMail frederik at remote.org ## N49°00'09" E008°23'33"
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