Re: [Maposmatic-dev] Possible bug: old files are kept when a city is re-rendered

[Jeroen van Rijn]

On Wed, Jan 6, 2010 at 18:49, David MENTRE <address@hidden> wrote:
> Hello,
>
> Following a question by cworth on IRC, it appears that if we re-render
> a city after the 24h time-out, new files are created but old ones are
> *not* erased. This is not an issue regarding disk usage, the daemon
> will remove older files. But the daemon might remove files from other
> cities, rendered before, while we want to keep them.

On one hand I'd say make the daemon keep at least one version of any
given city. On the other it's a question of how likely administrative
borders are likely to change over time (because of refinement of the
actual borders on the map, or because the border has in fact change,
lots of hamlets have a tendency to merge into larger villages).

In other words, how useful is an old version of a map with the exact
same bounding box going to be after a given time. Let's face it,
there's a lot of churn (in a good way) on the OSM data set, and
they're much more likely to show new road construction than other
maps.

Would be an idea to keep the single newest version regardless of age,
and display that if the user requests a map for that area. The user
can then request a newer map if it's deemed to be too out of date, or
they can just download the existing one. Perhaps show the slippy map
side by side to have them gauge if it's worth having to ask the server
for a new render.

Regards,
 J.