On Fri, Apr 18, 2008 at 4:56 PM, Frederik Ramm <[EMAIL PROTECTED]> wrote:
> Hi, > > That way you can call the osmxapi url with [polygon=belgium] or > > > [polygon:country=belgium] > > > > > > What do the osmxapi developers think about it? > > > > > > > > It's a nice idea. I just need to implement the algorithm described > > earlier > > in this thread :) > > > > Not only do you need to implement the algorithm, you also need a computing > environment that will be able to execute the algorithm in an acceptable > timeframe. A halfway "correct" border polygon of a landlocked state easily > runs into five-digit numbers of polygon nodes, and then for each of the 250 > million nodes in the database, you have to find out whether it lies in that > polygon. > > (An obvious optimization is to compute the largest rectangle contained in, > and the largest rectangle containing, the polygon. First check if point is > outside the outer bbox - if yes, you're done. Then check if point is inside > the inner bbox - if yes, you're done. Only after that do the actual polygon > test.) > Yes, the algorithm is simple, it's implementation is a little more challenging. > > Bye > Frederik >
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