[Talk-us] Poor JOSM Yahoo imagery solution?

Frederik Ramm frederik at remote.org
Tue Nov 24 03:20:44 GMT 2009


Alan,

Alan Mintz wrote:
> Is anyone working on a solution to the poor Yahoo image quality in JOSM 
> (compared with Potlatch, browser, etc.)? This pic shows the striking diff 
> between the same area at the same scale in JOSM and in Potlatch: 
> http://sites.google.com/site/am909geo/osm-1/BadYahooImagery.jpg?attredirects=0

Interesting. When I call up this area in JOSM, or indeed using any 
standard "Yahoo Map API" example, the image URLs that are retrieved look 
like this:

http://maps1.yimg.com/ae/ximg?v=1.9&t=a&s=256&x=22784&y=13251&z=1

That's the best zoom it gives you (z=1, smaller being better). So JOSM 
plays according to the rules of the Javascript API. However using 
Potlatch, which presumably uses a Flash API, the map tiles requested 
look like this:

http://us.maps3.yimg.com//aerial.maps.yimg.com/img?md=1204827325&x=45569&y=26502&z=19&r=1&v=1.7&t=a

and have a better resolution - z=19, higher being better in this scheme.

The key to fixing this in JOSM would be finding a way to get the 
high-res imagery through the Javascript interface. So if anyone would 
manage to modify any of the examples on

http://developer.yahoo.com/maps/ajax/

to actually give you the high-res image then we could use that knowledge 
to improve JOSM. (I'm cc'ing this to the JOSM-dev list.) - We are not 
allowed to cheat our way out of the Javascript API, sadly, which means 
we cannot retrieve the tiles directly even if we knew how to.

Bye
Frederik

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




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