Changeset: 47241744
Netherlands, around Den Dungen, tidy landuse/natural
Closed by bdiscoe
Tags
created_by | JOSM/1.5 (11639 en) |
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source | Bing |
Discussion
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Comment from de vries
Hi bdiscoe,
I need to ask you to be more careful with edits like these. In this changeset you seem to have targeted BAG buildings for mass simplification. The methods and software used for importing and actualization of the BAG data has been discussed in great length. So doing mechanical edits to the data without consulting the local community is kind of rude. If you're having issues with the quality of the data, I suggest that you discuss them at the Dutch forums.
Also in another changeset nearby you mass simplified landuses. In this changeset you removed detail from a lot of landuses that were hand-traced from very high resolution imagery. I'm not amused by that one either.regards, de vries
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Comment from bdiscoe
Hi, if you take a close look, you will see that no "details" were removed. As part of other cleanup (maproullette farm->farmland), I've been run the JOSM validator on some of the nearby buildings and landuse, and tidying up the results. The BAG buildings have numerous issues (including tiny slivers of geometry that are obviously artifacts) which i clean up along with other bad modelling. The is also overlapping identical landuse (which i fix) and some very poor overnoding (which i fix). I am an expert at what I'm doing and I'm happy to defend any node or way that anyone has an issue with. The final result is a map that loads and renders faster, is free of topological issues, and is easier to manually maintain.
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Comment from bdiscoe
For what it's worth, I recognize unlike other mass imports I'd had to clean up (Canvec, NHD, Tiger...) this data is much better in precision as well as accuracy. That's why i use thresholds not of 70-110 cm as with NHD, but as little as 6 cm for BAG, guaranteeing that cleanup stays within the accuracy of the source data and everything is improved, absolutely nothing is lost.
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Comment from bdiscoe
For an example of BAG problems, see buildings like http://www.openstreetmap.org/way/277899879 which has a "sliver" which is 18cm wide and 3m long; it is clearly a mechanical error. I have manually fixed hundreds of these problems.
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Comment from Commodoortje
Hi bdiscoe,
Thank you for fixing the JOSM validation errors on BAG import here.
The person who did the BAG import is responsable for fixing duplicated nodes/crossing buildings/building inside building self-intersecting ways etc... -
Comment from de vries
You had me at "I am an expert at what I'm doing". But if you want an example: compare this two images:
http://pix.toile-libre.org/?img=1493650984.png
http://pix.toile-libre.org/?img=1493651063.png
The imagery resolution is 7,5 cm so your simplification is nowhere within the accuracy of the source data. this is just one of the many examples available.
I also have doubts about your claim that you did all this deletions manually. because after this chageset it took you only 16 minutes to make a changeset of 5512 changes.
But I have to compiment you on the way you completely ignore the point I was trying to make about how you do mechanical edits without consulting the local community, the original editors of the data, who still maintain it or the automated edits code of conduct. -
Comment from Commodoortje
Het lijkt erop dat bdiscoe in JOSM de functie "Simplify Way" gebruikt.
Wat deze tool doet: de contouren ontdoen van onnodige nodes.
https://josm.openstreetmap.de/wiki/Help/Action/SimplifyWay
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Ik ben het met de vries eens dat dit niet structureel op gebouwen mag plaatsvinden. Dan wordt namelijk de nauwkeurigheid uit het object gehaald.
Als voorbeeld wil ik de kerk gebruiken.
http://www.openstreetmap.org/way/271108474
Als "simplify way" op dit object wordt toegepast, is de vorm van het gebouw geruïneerd.
Onderstaand plaatje laat de contouren zien na "simplify way"
Op de achtergrond hoe het origineel was.
https://www.dropbox.com/s/ufa79ytiki2u0ep/2017-05-01_17-49-21.jpg?raw=1
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