[OSM-dev] diffs in rails port and josm for the same algo

[Martin Schafran]

hi,

josm and rails port have different world parts. 65535 and 65536.

testing at bounds
for eg. at lon=180 we get different results, namely 65535 or 65536.

am I right?

look at this in quad_tile.rb

def self.tiles_for_area(bbox)
      minx = ((bbox.min_lon + 180) * 65535 / 360).round
      maxx = ((bbox.max_lon + 180) * 65535 / 360).round
      miny = ((bbox.min_lat + 90) * 65535 / 180).round
      maxy = ((bbox.max_lat + 90) * 65535 / 180).round
      tiles = []

      minx.upto(maxx) do |x|
        miny.upto(maxy) do |y|
          tiles << tile_for_xy(x, y)
        end
      end

      return tiles
    end




and this in josm QuadTiling.java

double WORLD_PARTS = 65536.0;

public static long lon2x(double lon)
    {
        //return Math.round((lon + 180.0) * QuadBuckets.WORLD_PARTS / 
360.0)-1;
        long ret = (long)((lon + 180.0) * WORLD_PARTS / 360.0);
        if (ret == WORLD_PARTS) {
            ret--;
        }
        return ret;
    }



martin
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