Frederik Ramm wrote > > > On 07/13/2012 04:59 PM, nimix wrote: >> If I remember it right mapnik requires normalized geometries, so outer in >> clockwise and inners in counterclockwise order. I'm not sure if that is >> still the case, but osm2pgsql still does the normalization. That's why I >> defined the result in clockwise orientation... > > Mapnik doesn't require that as far as I know (have to check though). > However, if you e.g. create a shape file and open that in ArcGIS and > compute the polygon area, it will come up with negative areas if your > polygon goes the wrong way round. > >
Hi, I just has a look at this... Mapnik indeed has no such requirement. But it requires inner rings of multipolygons do be in a different orientation than the outer ring. Hence it is reasonable to ensure that by just making all outers cw and inners ccw. -- View this message in context: http://gis.19327.n5.nabble.com/New-OGR-driver-to-read-OpenStreetMap-osm-pbf-files-tp5715906p5716533.html Sent from the Developer Discussion mailing list archive at Nabble.com. _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
