[OSM-dev] "Retina" tiles - best way to support them?

Frederik Ramm frederik at remote.org
Thu Jul 5 10:11:05 BST 2012


On 07/05/2012 10:32 AM, Martin Koppenhoefer wrote:
> Btw.: the tiles are NOT identical also apart from the resolution, look
> e.g. at Fürth: on the normal tiles there is Erlangen above it, while
> on the hires tiles it isn't.

Yes, but that's just normal style idiosyncracies - whatever comes first 
is rendered first, it's more or less random.

> On the other hand it wouldn't even be desirable (IMHO) to have the
> exact same tile at a higher resolution. To make best benefit from more
> pixels on the display it would be ideal to have a dedicated style to
> be able to get more details on the "same" zoom level.

Probably depends on just *how* much bigger your resolution is.

> Another thing is that on mobile devices traffic and loading speed are
> often an issue, and upscaled images (standard tiles at 200%) are
> generally "sufficient" for most users I guess

Sure. When CloudMade launched their tile service a while ago, they even 
offered a special "mobile" style designed to produce tiles that use less 
space, and I believe they even cut tiles to 64x64 or so in order to 
reduce unnecessary downloads. It is clear that double-resolution tiles 
like the ones I made here are a luxury that only those with lots of 
bandwidth and storage space will want to afford.

> To overcome these issues rendering on the device could be a solution

Yes, I think rendering on the device is certainly the future, and bitmap 
tiles will probably be phased out in a couple of years, except maybe for 
overview maps on very low zoom levels.

> This would even
> lead to a native stepless zooming experience (like a WMS), and the
> vectors could maybe be used for other things as well (routing (?),
> feature search and highlighting).

All of that is already available in commercial applications like 
Skobbler's ForeverMap today and there are already promising Open Source 
in-browser rendering engines so it's pretty clear that this is where the 
journey goes. I'm not making high-resolution tiles as a replacement for 
vector rendering - just as an interim solution until vector rendering 
for the masses is actually here.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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