Multiploygonal waterways should be big and giant? Or split?

[olliv3r]

Hi,

I’ve been going over out local map, which has really strange splits on rivers near/under bridges. Mind you, this is the NL map so all this data was donated and imported.

My question really is more general. Waterways, rivers etc. Should they be one giant multipolygonal over the area they spawn? E.g. from the mountain they spring of, until the ocean they flow into? Or until the river they merge in? Or is it advisable for performance reasons to have these polygonals split every so often.

[stephan75]

splitting is better than having one very big object.

I think there is even a limit when uploading edited or new data to the main OSM database by 2000 nodes per way segment maximal.

[Tordanik (Tobias Knerr)]

@olliv3r

My question really is more general. Waterways, rivers etc. Should they be one giant multipolygonal over the area they spawn? E.g. from the mountain they spring of, until the ocean they flow into? Or until the river they merge in? Or is it advisable for performance reasons to have these polygonals split every so often.

The splits are very helpful for performance, maintenance and the avoidance of editing conflicts. Therefore multipolygons should only be used for islands in the river etc., not for connecting multiple segments into a big area.