[OSM-talk] Bing coverage - more levels

[Eugene Alvin Villar]

Don't forget that because of the Mercator projection we use, a level
20 tile at the equator (like Singapore) shows the same spatial
resolution as a level 19 tile at latitudes near 60 (N or S, like
Helsinki).

Helsinki at level 19:
http://www.bing.com/maps/?v=2&cp=60.17150065552734~24.93957236409227&lvl=19&dir=0&sty=a
Singapore at level 20:
http://www.bing.com/maps/?v=2&cp=1.3051193488899742~103.83200242146012&lvl=20&dir=0&sty=a

Note that the scale bar at the bottom of both views are practically the same.


On Wed, Feb 9, 2011 at 4:52 AM, ant <antofosm at gmail.com> wrote:
> Hi all,
>
> I've been thinking about extra colours for super hires imagery and been
> doing a little research. See the following list of some notable places
> sorted by their highest Bing zoom levels.
>
> Hamburg 20
> Vienna  20
> London  20
> Rome    20
> Paris   20
> Tokyo   20
> Singapore       20
> Montreal        20
> New York City   20
> Denver  20
> Los Angeles     20
> Kansas City     20
> Mexico City     20
> Port-au-Prince  20
> Munich  19
> Helsinki        19
> Madrid  19
> Warsaw  19
> Moscow  19
> Istanbul        19
> Delhi   19
> Tunis   19
> Perth   19
> Sydney  19
> Amsterdam       19
> Netherlands rural areas 19
> Stockholm       19
> Bogota  19
> Santiago de Chile       19
> Beijing 18
> Cape Town       18
> Rio de Janeiro  18
> Berlin  17
> Dublin  17
> Damascus        17
> Cairo   17
> Lagos   17
> Germany rural areas     17
> Kansas rural areas      17
>
> It seems that all places that have hires imagery of z14 also have it up to
> z17 (of which z14-z16 are scaled versions, of course). So no need to
> introduce extra colours for anything below z18. Then the question is: How
> many colours make sense between z18 and z20 (the absolute maximum)?
>
> I think one colour for each zoom level doesn't make sense, because the
> overall differences in image quality are too stark (compare for example NYC
> and Santiago de Chile at z19, respectively).
>
> So what about:
> 14-17   "high resolution"
> 18-19   "very high resolution"
> 20              "ultra high resolution"
>    ?
>
> And... which colours? I would have liked a kind of red-yellow-green scale,
> but I'd rather keep the green now in order to avoid confusion (old green
> tiles vs. new green tiles and so on). So I propose a dark green for "very
> hires" and a blueish green for "ultra hires" -- see the screenshot.
>
> In anticipation of your comments,
>
> ant
>
>
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>
>



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