[OSM-dev] tiles cut corners

[Ben Gimpert]

On Sat, Feb 25, 2006 at 08:32:17PM +0100, Lars Aronsson wrote:
> This code is hard to read as it is, and it doesn't get better from 
> the fact that lat2 < lat1 even though lon1 < lon2.  The call is 
> dao.getnodes(trlat, bllon, bllat, trlon), whereas the argument 
> order in the CGI interface is bbox=bllon,bllat,trlon,trlat.  I 
> must admit I don't fully understand what this deeply nested SQL 
> statement does.  For example, where do "b" and "c" go?  Does this 
> statement select any node outside of the current tile?  Isn't it 
> in fact equivalent to the following?
> 
>   select id, latitude, longitude
>   from nodes
>   where latitude > minlat
>     and latitude < maxlat
>     and longitude > minlon
>     and longitude < maxlon
>     and visible = true

No, you need the subselect (or its equialent) to get the newest elements
in the bounding box. (It's a wiki, right?)

		Ben