On Fri, Dec 2, 2011 at 1:15 PM, Maris Nartiss <[email protected]> wrote: > Hello, > that makes sense. > > Might I suggest to take a look at JTS Topology Suite Technical > Specifications fig. 6 that seems to display most common issues that > could be eliminated with GRASS cleaning tools too.
Thanks for the suggestion! Fig. 6 shows what I tried to explain, and some more. Markus M > > Maris. > > 2011/12/2 Markus Metz <[email protected]>: >> On Fri, Dec 2, 2011 at 12:43 PM, Maris Nartiss <[email protected]> wrote: >>> Pardon my ignorance, >>> how is possible to distinguish areas without centroids from holes? >>> And why it doesn't make sense? >> >> A hole is a nothing in a something. If there is no something all >> around the hole there is no hole. IOW, an area without a centroid is a >> hole if it is completely surrounded by other areas with centroids, >> otherwise that area is not a hole because it shares one or more >> boundaries with the outer void. This does not make sense logically >> because then there are two indistinguishable voids bordering each >> other. These two voids can just as well be combined into one, lest >> there is something special about one of the two voids, but that you >> could only tell if there is a centroid in one void, rendering it >> non-void. >> >> Markus M >>> >>> Maris, >>> just finished converting and cleaning CAD (spaghetti) lines + points >>> to valid areas. >>> >>> 2011/12/2 Markus Metz <[email protected]>: >>>> >>>> * for areas without centroids that are not holes. Areas without >>>> centroids that are not holes are topologically correct but do not make >>>> sense logically. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
