Changeset: 42671939
Restored field borders on Echerfeld. Simplified multipolygons.
Closed by Stereo
Tags
created_by | JOSM/1.5 (10966 en_GB) |
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source | geoportail.lu Photographies aériennes orthorectifiées 2013 |
Discussion
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Comment from mavl
Hello, Stereo. What wrong with way?
http://www.openstreetmap.org/way/372411024/history
You wrote "Simplified multipolygons." Why?
If something is marked as multipolygon, then it's ok. -
Comment from Stereo
Hello mavl,
Thank you very much for your message. It's always interesting to think about mapping practice.
Before my edit, there were 28 multipolygon relations, many of them consisting of only outer ways.
After turning these into areas, and using big inner islands to contain groups of landuses inside the forest, this is down to 3. Relation 103843 is down from 55 to 34 members.
Simple polygons should be preferred to multipolygons:
- It goes against common usage: mappers are used to using closed ways for, say, landuse=farmyard when it can be traced as a simple polygon.
- It makes editing tedious and error-prone: I know the changeset area well, but found it [through the osmose QA tool's multipolygon checker](http://osmose.openstreetmap.fr/fr/errors/?country=luxembourg&item=1170). Have you tried editing one of these big relations we have in Luxembourg, in iD or JOSM?
- It makes the data hard to understand and process. There are many edge cases if you start mapping everything like this, and different renderers understand multipolygons differently.
I'd be interested to hear what you think.
Guillaume
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Comment from mavl
Thank you so much for your answer.
«there were 28 multipolygon relations, many of them consisting of only outer ways»
Maybe, the contributor has not finished work yet.
I have looked the data in iD and in JOSM. It looks as in other places of a planet (as usually). If we have a lot data then we can make a mistake easy (with multipolygons, with ways with the big number of the common nodes).
I believe that the simplification of the data is an element of data degradation. Multipolygons exist for a long time and it is used by people and programs successfully.
- «It goes against common usage: mappers are used to using closed ways»
It is subjective criterion. There are people which use multipolygons.
- «It makes editing tedious and error-prone»
Also subjective criterion.
- «It makes the data hard to understand and process»
Also subjective criterion.I think that if the data exist without errors, then we should not edit them for simplification.
OpenStreetMap stands on one place when one contributor creates the data, but another contributor simplifies it.
- 446017143, v1
- 446017144, v1
- 446017145, v1
- 446017146, v1
- 446017147, v1
- 446017148, v1
- 446017149, v1
- 446017150, v1
- 446017151, v1
- 446017152, v1
- 446017153, v1
- 446017154, v1
- 446017155, v1
- 444985161, v3
- 446017156, v1
- 446017157, v1
- 446017158, v1
- 446017159, v1
- 446017160, v1
- 446017161, v1
Relations (1-20 of 28)
- 1
- 2
- Bambësch (103843), v25
- 6624626, v3
- Piste cyclable du Centre (PC 1) (31623), v204
- CFL 17 (2251561), v17
5537520, v25537521, v25537500, v25537501, v25537502, v25537503, v35537496, v25537497, v25537498, v26624619, v35537499, v25537508, v45537509, v25537510, v35537504, v25537505, v4
- Pilatusbierg (4433489498), v1
- 4433489499, v1
- 4433489500, v1
- 4433489501, v1
- 4433489502, v1
- 4433489503, v1
- 4433489504, v1
- 4433489505, v1
- 4433489506, v1
- 4433489507, v1
- 4433489508, v1
- 4433489509, v1
- 4433489510, v1
- 4433489511, v1
- 4433489512, v1
- 4433489513, v1
- 4433489514, v1
- 4433489515, v1
- 4433489516, v1
- 4433489517, v1
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