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openstreetmap / iD

🆔 The easy-to-use OpenStreetMap editor in JavaScript.
https://www.openstreetmap.org/edit?editor=id
ISC License
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Polygon rounding creates too many nodes #8389

Open MichaelMontani opened 3 years ago

MichaelMontani commented 3 years ago

When rounding closed ways on iD with the 'O' shortcut, iD creates a standard circular polygon with number of nodes that seems vary between 19 - 36. This has been causing problems in mapping, especially when newbies add many circular huts: adding 19 nodes for an hut which is 1-2 meters long adds unwanted complexity to the data causing problems with download of OSM data, especially when they are many.

On JOSM, the 'O' shortcut makes polygons circular keeping constant the number of nodes of the polygons. Shouldn't be this method be preferred instead of dropping 19 nodes each time? It is possible to validate this on JOSM, but wouldn't be better to create rounded polygons with less nodes, or keep the number of nodes constant?

Screenshot from 2021-03-10 09-37-37

matkoniecz commented 3 years ago

adding 19 nodes for an hut which is 1-2 meters long

This is perfectly fine in mapping.

causing problems with download of OSM data

Can you be more specific where and how this problem is happening?

MichaelMontani commented 3 years ago

This is perfectly fine in mapping.

Technically fine but very bad mapping in my opinion. An hut of 1-2 meters doesn't need 19 nodes, and the same hut with way less nodes is fine as well.

Can you be more specific where and how this problem is happening?

Tens of thousands of huts like these ones are making it difficult to download the area from JOSM or for any use. We validated the area (which was previously mapped by others in https://tasks.hotosm.org/projects/10189) but would be easier if newbies wouldn't be able to create 19 nodes 1-2 meter huts simply by clicking the 'O' key in iD..

bhousel commented 3 years ago

This has come up before in #2061 and #3565..

matkoniecz commented 3 years ago

Is it about objects like https://www.openstreetmap.org/way/901270415 ? Again, looking at it - that seems 100% fine and preferable to lower accuracy.

It is not "very bad mapping".

MichaelMontani commented 3 years ago

Checking the imagery, it seems too blurry to me to state those are totally circular huts. More nodes doesn't mean better accuracy. You can express the same information accuracy using less nodes, especially when it's not so clear they are actually circular.

matkoniecz commented 3 years ago

iD is unable to stop mapper using circles for something that is not a circle.

For "polygon rounding creates too many nodes" it is not relevant whatever specific circular geometries are represent objects circular in reality.

In the same way as iD will be unable to stop mapper mapping fake rivers or fictional cities.