[Routing] SVG instead of tiles  was: Routing web-services

OJW streetmap at blibbleblobble.co.uk
Tue Nov 20 19:53:54 GMT 2007


On Tuesday 20 November 2007 16:57:13 Robert (Jamie) Munro wrote:
> In all off-line cases, we should be downloading vectors and drawing the
> map on the client. They are much smaller, and they can be scaled,
> rotated and 3d projected, while keeping the text facing in a sensible
> direction. They can have any elements hidden or displayed, then can be
> directly routed over without needing another set of data.

well show us some vector map viewers that outperform image ones then... all 
that scaling, rotating, and 3d projection (on every node in view, and lots of 
nodes not in view) all takes time.

it's not even the same data as you want for routing.  The routefinder doesn't 
care what *name* a street has, only how fast you can get down it with a herd 
of camels.

I guess the tiles at home project should be able to tell us a bit about the ratio 
of image size to OSM data size to SVG size for each tile.  And about the CPU 
power required  (last I heard, it was 2GB minimum RAM and quad-core CPU for 
rendering an SVG of central London)

I did look at using the vector data for display in pyroute.  And I got results 
looking similar to all the other vector map displays -- i.e. that the maps 
are very slow and very ugly.







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