Jochen123 wrote > > > I think I agree with your here. Whether a simple polygon is valid or not > that > tells us the Simple feature definition. Software that turns single ways > into > single polygons should only look at one thing: If the way is closed, it is > porentially a polygon and can be converted to one. The conversion is > straightforward and easy. The software is not supposed to fix ways that > might > result in invalid polygons. The result is a Simple Feature polygon and if > some application wants to check whether a polygon is valid, it can do so. > If it is valid, the way was valid, if not, then not. > > The case for multipolygons is different. Here there are several ways and a > relation involved. It is much more difficult to assemble the raw data into > a multipolygon. What we want to agree on is how exactly this assembling is > done. It might be if you follow the assembling process exactly the result > is an invalid multipolygon. Thats okay. > > We are not trying to make sure there aren't any invalid geometries > generated. > We are trying to make sure we agree on the result of the conversion > process, > may it be a valid (multi)polygon or an invalid one. > >
Ok so, we can agree that in the closed way testsuite everything except 1,2 is invalid. I added .result files indicating that to the repository. But I don't like the idea to define the expected output to invalid geometries. There should be either a reasonable result or nothing. Otherwise it is impossible to have a repairing algorithm passing the test... Just a minute ago a also added a testcase for geometry output of multipolygons. Again we need to discuss which cases are valid and which are not. So far my opinion is: 1-3, 6-8 valid 4-5, 9-10 invalid Again for those not willing to look into github. I am talking about multipolygons in [1] from bottom to top. [1] https://dl.dropbox.com/u/58628/multipolygontest.osm Regards, Melchior -- View this message in context: http://gis.19327.n5.nabble.com/New-OGR-driver-to-read-OpenStreetMap-osm-pbf-files-tp5715906p5716524.html Sent from the Developer Discussion mailing list archive at Nabble.com. _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
