Hi Vincent, > I know this is old stuff (references below), but making polygons instead > of lines would be a great option for gdal_contour IMO. > > It could be also another program included in gdal/app (if it is already, > I can't find it). > > What do you think, shall I add that ? If yes, first or second option ?
I had a similar problem years ago, and after making consistent orientation [1] it is simply a matter of running through the lines and matching starting points with endpoints in the linestrings. This is a rather fast operation on a spatially indexed dataset. You cannot always make polygons with them unless you are on a perfect island - for instance I processed Denmark in tiles (over 43000 tiles of 1x1km) and then "glued" the linestrings together afterwards. Speed was essential, so I first glued all linestrings in a tile (which would make a large number of closed linestrings), then between tiles (but only for those that were not yet closed). Cheers, Gregers [1]: https://trac.osgeo.org/gdal/ticket/3129 _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
