[OSM-dev] [PATCH] osm2pgsql tile expiry

Martijn van Oosterhout kleptog at gmail.com
Sun Feb 8 11:37:51 GMT 2009


Looks like a pretty cool idea. I only have a few small comments.

- The use of -o. Is there any other output osm2pgsql could produce
that would be more logical. Not really a big deal, the long option
expire-output is there which is good enough for me.

- There a whole new file added (expire-tiles.c) which seems to have
some kind of tree structure. Do you think you could add a comment at
the beginning what kind of structure it is and any relevent invariants
(like middle-ram.c does).

- Does middle.h need to include osmtypes.h?

- You've got a definition of EARTH_CIRCUMFERENCE. Does that match with
what's used in the projection code?

Other than that I have no objections (I assume it doesn't change
anything when not run in this mode).

Have a nice day,

On Sun, Feb 8, 2009 at 11:23 AM, Steve Hill <steve at nexusuk.org> wrote:
>
> I've been working on code to generate a list of dirty tiles while importing
> the deltas.  The attached patch introduces 2 new commandline options: "-e
> <zoomlevel>" and "-o <dirty tile list output file>".  So, specifying "-e 17
> -o /tmp/dirty_tiles" when importing a delta will cause osm2pgsql to generate
> a list of all zoom level 17 tiles which the delta has made dirty and store
> it in /tmp/dirty_tiles.
>
> Proviso: for polygons, it currently takes a simplistic approach of drawing a
> bounding box around the whole polygon and marking every tile in the box as
> dirty.  If the bounding box is large (over 30x30Km) the polygon is treated
> as a line instead, so only the perimeter will be marked as dirty (this is so
> that huge polygons don't expire vast numbers of tiles and is based on the
> assumption that we probably aren't going to shade the area of massive
> polygons).
>
> The dirty tile list is maintained in memory as a binary tree and dumped to
> disk at the end of the run.
>
> I'm running this code on OpenPisteMap and it seems to be working ok.  Does
> anyone have any objection to me committing these changes to the
> OpenStreetMap subversion server?
>
>  - Steve
>   xmpp:steve at nexusuk.org   sip:steve at nexusuk.org   http://www.nexusuk.org/
>
>     Servatis a periculum, servatis a maleficum - Whisper, Evanescence
>
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>



-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/




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