[Tilesathome] lowzoom rendering takes forever?

[Hakan Tandogan]

spaetz wrote:
> On Sat, Nov 24, 2007 at 12:18:57PM +1100, Brent Easton wrote:
> 
>> I believe there is nothing wrong, that's just the way the new lowzoom works. 
>> The amount of data downloaded in a z8 tile can be huge for areas around well mapped cities. 
> 
> As the guy who initially did the "new lowzoom" I would like to comment on the situation. It was an experiment as I was annoyed by unreadable text at low zoom levels and want to play with Etienne's osmxapi. However given the scaling problems we see, I am convinced that this is the wrong approach and should be turned off until we have something feasable.

No, please don't turn off the lowzoom rendering. The readable place 
names on lower zoom levels (say, z8 or so) are simply too useful, 
especially for larger countries which consist of multiple z8 tiles.

People can already tell the server that their machines are not capable 
of rendering lowzoom tiles. Perhaps we could even use the server 
feedback to automatically determine people who can render lowzooms.

> I only see 2 solutions:
> 1) Implement a simplification preprocessor that cuts down the OSM files to a manageable complexity (no need for a 1m resolution when you squeeze half of the UK on a tile).

A preprocessor that determines how many meters a pixel on a given tile 
would be and selectively removes nodes from ways? Seems like an 
interesting experiment.

> 2) Render a z12 which is geared for lowzoom generation, ie without text and just with the major roads etc. Then stitch them together for lowzoom tiles and overlay them with a transparent text layer. To make IE happy, we would probably merge down both layers in one PNG file.

I think the first solution would be the better one.

> I don't have the time or motivation at the moment to implement either solution, but this is what I think would make osmarender lowzoom work.



Regards,
Hakan


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