[OSM-dev] osm2pgsql, -e option might affect too many tiles

[Andy Allan]

I'm not sure that osm2pgsql is massively sophisticated with this
situation, since it certainly doesn't know anything about the
stylesheets.

If, for example, the node was moved slightly, and all those lines were
dashes, then the full length of every line would need to be redrawn.
Alternatively, if it was just a tag change but now became e.g. a pub,
then any blocking symbolizer along those lines (e.g. road names) could
have moved and again everything needs redrawing.

That said, I'm sure there's plenty of optimizations that can be made
in this area.

Cheers,
Andy

On Thu, Sep 1, 2011 at 7:10 AM,  <marqqs at gmx.eu> wrote:
> Hello,
>
> I'm using osm2pgsql with the excellent -e option which allows me to generate dirty-tiles lists. It's my observation that the output can be somewhat extensive if you just change ONE node. For example:
>
> I change the name of a single node. This causes osm2pgsql to put not only the node's tile on the list but also every tile which is touched by every way which uses this single node. I guess there's a reason for this behaviour. Does anybody know situations in which it is really necessary to rerender all these ways?
>
> Markus
>
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