[OSM-talk] Multilingual maps demo

[Laurence Penney]

Cool stuff!

A while back I sketched out some ideas for something quite similar. Its v1 would have been along these lines with transparent PNGs. But v2 would have sent text labels as a JSON structure containing text plus xy or latlong positions, for rendering on the client. This way you can make separate decisions about text quality and map quality, potentially serving very compressed JPEG maps, and you get very quick rendering of placenames, they'd render before the tiles and you could potentially use only the labels, no tiles, where bandwidth was expensive — and you get quick client-side language changes.

With the high frequency text components removed from map tiles, you can get away with much more aggresive compression. I'd love to turn down the quality of Retina map tiles when roaming!

I was recently reminded of the benefits of separating text foreground (high freq, so compresses poorly) and image background (low freq, so compresses well) by examining the images embedded in some PDFs of scanned books at archive.org. I think they must have been converted from master files compressed for DjVu, where this separation is normal.

http://en.wikipedia.org/wiki/DjVu#Compression

- L

On 30 Nov 2012, at 14:34, Jochen Topf <jochen at remote.org> wrote:

> Hi!
> 
> I have been working on a multilingual OSM map, ie. a map where you, the user
> can decide in which language the labels should be. A demo of the system is
> now available at http://mlm.jochentopf.com/ . The tiles for this demo are
> rendered on tile.openstreetmap.de, the software used is the MapQuest Render
> Stack with modifications by me. You can choose any language or language
> combination for the labels.
> 
> This is only a demo, the site might be slow or not work at all. Please try
> it out and tell me what you like and what you don't like.
> 
> For more about this project see:
> http://wiki.openstreetmap.org/wiki/Multilingual_maps_Wikipedia_project
> 
> Jochen
> -- 
> Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298
> 
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