WoodWoseWulf (2021-12-01 04:00:03+00:00): Hiya Andrew,

Thank you so much for taking the time to write such a detailed reply to my questions.

> “I haven't found any reference material on which approach to apply when. Is it just a case of 'scale'? What are the ‘cons’ of closed ways?”

I suggest checking out this wiki page: https://wiki.openstreetmap.org/wiki/Relation:multipolygon towards the bottom, there’s a really great breakdown under the header “Mapping Style, Best Practice”. As with almost everything on OSM, there’s a debate there, but for me it comes down to the last point regarding sparing a consideration for future mappers and being wary that making things needlessly complex is just asking for something to go awry at a later point in time. 

On the Coast, we’ve generally been moving away from having smaller parks and similar areas formed out of complex collections of dozens of ways as it makes things really, really hard to maintain as all the new development occurs here (especially around the north end of things where new places are being built all the time).

> “I’ve redone the park (and swimming area) as closed ways, and merged some of the split ways. Is this now correct?”

This looks better, but you’ve got the park as a one-member relation – the relation that was the park can be removed and the tags can be moved back to the way that forms the area.

>”use the DCS base map to define residential areas strictly, with those that go to the lake edge separate to the areas that don't; splitting the lake edge line at the points where the residential meets the lake and create a relation there. This does look clumsy as I didn’t apply the correct road/residential area interpretation everywhere.”

I wouldn’t be linking separate residential areas under a single relation, but aside from that, I personally think the areas you’ve created are generally okay, and your work is neat and tidy from what I can see. Just bear in mind that the landuse “ground truth” may occasionally differ from the DCS map, so you may need to think about some areas rather than just defaulting to what DCS thinks is there. Our job here is to map locations as they are, not just copy DCS – though that’s an easy trap to fall into.

There’s a few mapping styles of landuse in different parts of the Coast, I personally prefer the really detailed version that allows for roads, retail, and other non-residential features to be excluded. Though, so long as things are neat and tidy, I think we can all get along, haha.

If I’m mapping residential block-by-block, I typically won’t use a relation unless there’s something inside of an area like a large council-owned water basin or other non-residential feature.

> “similarly for land cover, I have created a way for the landside edge of lakeside woodland, even if it overlaps residential, and joined it to the Lake edge with a relation. (I thought I had done a similar thing along Dora Creek, but this renders differently, so probably not).”

For small areas of park/natural features, it may be easier both now and for others editing in the future to just create a single closed way area as opposed to making some kind of really complex series of relations between the water and adjacent landuse.

If the woods are part of a much larger area though, you may want to consider a relation still.

As things are in reality, landuse and landcover/natural features can intersect. I used to live in a house that was unquestionably residential, but I had rainforest woodland out the back that grew into my yard, The line was fuzzy and it’s generally ok to represent that in OSM by intersecting areas of that kind.

Best,

Wood