[OSM-dev] Can we have higher resolution tiles?

[Igor Brejc]

If you need printing-quality rendering, you can take a look at
http://maperitive.net/docs/manual/Commands/ExportBitmap.html#Scaling

Igor

On Wed, Jun 15, 2011 at 2:42 PM, Andy Allan <gravitystorm at gmail.com> wrote:

> On Wed, Jun 15, 2011 at 1:23 PM, Parveen Arora <osm at parveenarora.in>
> wrote:
> > On Wed, Jun 15, 2011 at 10:10 AM, Graham Jones <grahamjones139 at gmail.com>
> wrote:
> >> Hi Parveen,
> >> Do you mean resolution (pixels per inch) or level of detail (which icons
> >> appear at which zoom level?).
> > Yes I meant to pixels per inch.
> >
> >> You can change the resolution if you use mapnik2, but that is something
> you
> >> would want to do for printed output rarher than a web based map?
> > Yes, someone asked me to print them for his area, but one I printed is
> > not of good quality.
> > So I wants to increase the resolution of tiles for local OSM Tile Server.
>
> OK, so it's impossible to change the resolution of images, since they
> don't have a resolution. Images only have a number of pixels, that's
> it.
>
> When stuff is shown on screen it's usually shown around 90 pixels per
> inch. Most times when you print a webpage then it'll assume that you
> still want to print at 90 pixels per inch, regardless of the DPI of
> the printer. In order to look crisp, you want to find a way to
> instruct your printer to print at more pixels per inch, say 250 pixels
> per inch. Again, don't confuse this with the DPI setting of the
> printer, since that's about number of ink droplets on the page, and
> not to do with pixels per inch.
>
> Now to make things like the width of a road or icon of a church stay
> at the same size, you would need to increase the number of pixels they
> are measured in. So a road would need to be e.g. 15 pixels instead of
> 5. That usually involves changing the stylesheets, although there is
> work on this going on in mapnik2 to allow this to be controlled
> without editing the stylesheet.
>
> You could have a look at the "oversize" tiles that CloudMade produce.
> http://developers.cloudmade.com/projects/tiles/documents . You can see
> in the second example everything is drawn bigger, so that if you were
> to print out at 180 pixels per inch it would look the same size as a
> normal map, but you'll end up with a better looking map.
>
> Finally, if you are printing it's often worth ignoring all this stuff
> and just printing from SVG. You can get SVG output from the Export
> tab.
>
> Cheers,
> Andy
>
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