On Tue, July 3, 2018 7:20 pm, john whelan wrote: > I think my concern is more about the 'then a miracle occurs' in the > project plan to clean up the buildings.
Yes because, among other reasons: - For most people, verifying is not as gratifying as creating - Correcting entirely incorrect geometries is many ways more work than re-creating them from scratch I am not concerned about the most egregious cases: cars & trucks modelled as buildings, duplicates & superposed, rubbish heaps and vague shadows as building=yes, buildings found in old imagery... Those I delete with no hesitation. I am not concerned either about minor simplifications or errors such as the shape being traced on the roof of the building rather than its base - those I let them be and correcting them capitalizes on a good foundation. I am concerned about the cases where a building does exist in reality, the shape is less than ten meters from its position, some of the shape overlaps the building's position on the imagery and some of the shape resembles some of the building. In those cases, there is some value in the record: approximate position and area of the building. But there is also the liability of having introduced a low-quality object in the database. I am convinced that the immense majority of those buildings will never be corrected. In ten years, we can expect massive campaigns of automated image recognition to produce new building layers - but even then the extensive conflation will be an horribly tedious job. Meanwhile, for areas with reliable imagery, I can imagine Maproulette jobs: something in the spirit of "Does this building at least partially overlap one in the imagery and does it approximately resemble the one in the imagery ?". Those jobs could be designed at national or regional levels - under control of the local communities. They could be a way of systematic quality control. But maybe I'm horribly deluded about how many people would volunteer for such a mind-numbing task. Also, looking at buildings one at a time is very inefficient compared to panning through an area on JOSM - but then again, JOSM-enabled contributors that might be motivated for this are not exactly in plentiful supply either. And that does not even answer the question: what to do with the "low-quality shape but actually exists" cases ? I am at a loss to answer that. _______________________________________________ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk