[OSM-talk] OSM data, how can we contribute to keep it to a reasonable size?

[Oleksiy Muzalyev]

On 18.01.18 10:01, Martin Koppenhoefer wrote:
> 2018-01-18 6:14 GMT+01:00 Oleksiy Muzalyev 
> <oleksiy.muzalyev at bluewin.ch <mailto:oleksiy.muzalyev at bluewin.ch>>:
>
>
>     - deleting unnecessary nodes from a way (Shift-Y in JOSM) with
>     consequent verification of its geometry;
>
>
>
>
> please do not use SHIFT+y (simplify way / DouglasPeucker) because it 
> doesn't know about the actual geometry, in particular sharp bends or 
> curves in general will get worse, it will reduce overall accuracy 
> (within the distance limit that you set/default, but ignoring angles). 
> You will achieve better results by adjusting the ways manually. IMHO 
> applying this algorithm to geometries other than those you added 
> yourself is an automated edit and should generally be discouraged. 
> There are some sensible usecases (serious "overnoding", particularly 
> intermediate nodes in straight lines), but for every longer way (more 
> than a screenfull in reasonable zoomlevel) you will typically not see 
> all the effects, hence it's an automated edit.
>
> Cheers,
> Martin
Martin,

You are absolutely right. The Simplify way, Shift-Y, in JOSM, 
(Douglas-Peucker simplification) should be used only for own edits or 
for undeniable over-noding, i.e. a short direct line consisting from 
hundreds of nodes (probably from imports or kind of OCR editing).

Otherwise the lines and shapes will look angular.

I had to mention it myself. Thank you.

Best regards,
Oleksiy
osm: Alex-7


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