<span class="Apple-style-span" style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">I resume (first as a repeat to myself) what I've learned from the various email on the topic</span><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">
<br></div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">Vectors can be:</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">
<br></div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">LEVEL 1:</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">
- no topology -> very limited use</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">LEVEL 2:</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">
- unclean topology -> limited use</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); "> - clean topology -> full support</div>
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I previously thought that LEVEL 2 was only possible for clean topologies, and I was wrong...</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">
<br></div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">At the moment there isn't a tool to list the the uncorrect geometries from a topological point of view. v.build only checks some constraints, not all. The proposal is to extend it to check against all the rules that are required to consider a geometry topologically correct (an extended flag to v defaul.build maybe).</div>
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v.in.ogr builds and cleans (by default). It would be useful to have the "clean" phase available to be launched independently. I mean, something like an "automatic" flag for v.clean, that would operate the same cleaning as during the import of a vector.</div>
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Conclusions: the topological correctness isn't a constraint for the vector topology data structure. GRASS haven't all the topology rules hard-coded (... or yes?). Most of thems (all?) are defined inside the code of v.build and v.clean, but I suppose that there isn't an autonomous library/functionality that provide the semantics of a "correct topology". Am I wrong? </div>
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Thanks everyone for the support ;)</div><div style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 13px; background-color: rgba(255, 255, 255, 0.917969); ">giovanni</div>