[OSM-dev] Map rendering code... API or database direct?

Tom Carden tom at tom-carden.co.uk
Thu Mar 30 11:27:04 BST 2006


On 3/30/06, Raphaël Jacquot <sxpert at esitcom.org> wrote:
>
> there is another better way yet, available at the sql level...
> select all line segments that have a "foot" in the tile you're
> interested in.

No, the problem is that some segments don't have any "feet" in the current tile.

I am in favour of the suggestion to enforce a maximum line segment
length, so that tile code can just request a margin around the
required area and be sure to get all segments which pass through that
tile.  That's easier than thinking about going through all line
segments for all tiles, which would require a complicated spatial
index on the database to make it a viable process.

Alternatively, we query OSM for the longest existing segment length
right now, and enlarge all bounding boxes accordingly.

Tom.




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