Apparently there is a lot of mapping work going on for Haiti and Port-au-Prince. Maybe it would be a good idea to increase the speed of map rendering for Haiti if this was possible somewho.
OpenStreetMap
Apparently there is a lot of mapping work going on for Haiti and Port-au-Prince. Maybe it would be a good idea to increase the speed of map rendering for Haiti if this was possible somewho.
Discussion
Comment from amm on 15 January 2010 at 13:43
Which map are you referring to? The Main OSM (Mapnik) map, should be updated in about 2-5 minutes after new data comes in. Is this not working correctly? The t@h map is a little slower I believe with usually on the order of about 2 hours, but I am not too sure if that is still the case. I don't know how often other maps using OSM data update though
Comment from ALE! on 15 January 2010 at 14:09
On high (detailed) zoom levels the Mapnik is surely not updated every 2-5 minutes.
Comment from amm on 15 January 2010 at 14:50
Zoom levels 11-18 on mapnik are ment to be updated that often, but it might be that client side caching interferes a bit with that.
The way it works is that the mapnik rendering database is updated with the minutely-replicate diffs. Then the high zoom tiles that were affected by the diffs get "expired", which means that the next time someone views one of the expired tiles, it gets rerendered.
Altogether, the delay introduced from someone uploading changes till it being visible on the map should be (and normally is) about 1 - 5 minutes.
There are a couple of reasons why this might not be the case though.
For one, it might be that the server is overloaded so can't render all the expired tiles in time. This is rarely the case though and isn't at the moment, as the server is sufficiently powerful to handle all the render requests.
Secondly, some changes don't correctly expire tiles. The calculation of which tiles to expire might not take into account all the various complex relations, but again this should usually not be the case.
Another case is that the individual tile you are looking at takes longer than 3 seconds to render, in which case an old tile is serverd, to not drive up perceived latency
And lastly it could be that you have viewed the area before the changes, your browser / proxy then caches the tiles for a couple of hours and you don't see that the server has rerendered the tiles already.
Apart from the incorrect expiry, all of the above should normally be solved using a shift (forced) reload.
What sort of latecies do you see? Is it hours or days that changes don't appear? Anything more than a couple of minutes with the occasional hour long delay is a bug / problem somewhere.
But as I said, that only applies to the main "mapnik" OSM map and other maps may be very differently with some potentially only updating once a week or less.
Comment from ALE! on 15 January 2010 at 16:02
One example (not from Haiti) is this one:
osm.org/?lat=45.828588&lon=8.670336&zoom=18
Where it says "Enes". This was tagged as a building many days ago and the building does not get rendered.
Another example is the building here:
osm.org/?lat=45.8056698739529&lon=8.86397927999496&zoom=17
Comment from imroy on 15 January 2010 at 16:57
I checked that first link. Indeed "Enes" was on its own. Then I switched through the different renders and it showed up as a building (except Cycle Map is blank for some reason). I switched back to Mapnik and it then appeared as a building.
The funny thing is that I closed the tab, reopened it, and had exactly the same experience. I've since opened the individual tiles in my browser:
http://c.tile.openstreetmap.org/18/137385/93440.png
http://c.tile.openstreetmap.org/18/137384/93440.png
They initially showed no building. I did a shift-reload on each and it appeared. They then seemed to be 'permanently' updated in the slippy map. Something funny's going on with the caching of the tiles.
Note, I'm using Firefox/Iceweasel 3.5.6, behind a Squid 3.0 proxy.
Comment from davespod on 15 January 2010 at 17:07
Imroy, as you say, this is your browser caching the tiles. This always happens with the Mapnik tiles. I encounter it a lot, because I am impatient and like to see my edits rendered! If you don't want to do it a tile at a time, click on the Permalink link to ensure the address bar contains the Permalink, and then shift-reload.
Comment from imroy on 15 January 2010 at 17:35
But I've never viewed that part of the OSM map before I followed your link. So I can't have had those tiles in my browser cache. The OSM server gave me old tiles, then gave me new tiles when I shift-reloaded them. Was this because it took the server longer than 3 seconds to render each new tile, as amm described?
Comment from ALE! on 16 January 2010 at 13:46
Whatever I do, I can not make Mapnik make rerender my second example (a shopping centre near Varese):
osm.org/?lat=45.8056698739529&lon=8.86397927999496&zoom=17
Could you try?
Comment from davespod on 16 January 2010 at 15:43
My guess is that it is because node 393792143 is in the way twice:
osm.org/browse/way/34328295
However, I don't know how that happens (maybe someone else can shed some light on that?). If it were me, I would delete it and draw it again.
Comment from davespod on 16 January 2010 at 15:47
I'm talking nonsense - it looks like a node always appears twice in a closed way. I didn't realise that (kind of makes sense, I suppose). So, I have no idea! Sorry!