On Wed, May 8, 2013 at 9:49 PM, Nikos Alexandris <[email protected]> wrote: > Hi! > > .. > > Vincent Bainwrote: >> > Thank you Markus, >> > good news ! >> > how long has it been implemented ? > > Markus Metz wrote: >> The option to snap boundary vertices has been there ever since. The >> suggestion of a reasonable (assuming floating point rounding errors) >> threshold for snapping has been added 3 weeks ago, on April 19th. > >> BTW, if the input polygons are supposed to not overlap each other, the >> number of centroids should be identical to the number of input >> polygons (needs to be added to the manual). > > I tried to import USGS' (2011) Global Mangroves map: > > # stuff copied from the map's *latest* history > v.in.ogr dsn="/geo/geodata/mangroves/usgs_mangroves/usgs_mangroves2.shp" > output="global_mangroves_usgs_2011" min_area=0.0001 snap=0.000000000000001 > > 2018421 input polygons > Total area: 1.47005E+11 (2750605 areas) > Overlapping area: 5.32085E+09 (41540 areas) > Area without category: 9.25489E+09 (773734 areas) > > Twice the "error" message was like (even after I, by mistake, imported with > snap=1e-15): > > Ended with an "error while impoting, try to import with snap 1e-14" > > This means that there are still errors in the map, right?
I assume the global mangroves map should not have overlapping polygons, therefore as long as there are overlapping areas and/or the number of centroids is not equal to the number of input polygons, more cleaning is needed. Markus M _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
