Recently I have started contributing to OSM by mapping golf courses, and I am struggling with golf=rough. The current Wiki definition is it being the area between the fairway and the out-of-bounds (OOB).
However, it appears that there is also some user interpretation of “anything with an equal grass length to the first cut”. This results in roughs being mapped more like a spider web, because it includes grass paths and other areas with similar grass height (e.g. the Torrance Course in St Andrews, Scotland). This does not make sense to me: the golf ball is not in play if it lands on some random path, but OOB if it lands next to it. I flagged this on the golf=rough discussion page.
I contacted one mapper who uses this method, who explained that this method helps with video game mapping exports, as described in the Problematic mapping/golf wiki article.
I would like to update the wiki article on the tag to be a bit more specific regarding what should be mapped as the rough. If a mapper does a (very) detailed survey, it could be mapped in line with the Wiki guidance, but It’s impossible to see the out-of-bounds line on satellite imagery. This makes makes armchair mapping of the rough difficult.
My solution would be that the definition be made slightly more specific: the first cut of grass around the fairway, (and if possible up to the OOB line). Any grass-covered course paths, like dew walks, should be mapped as a path with the tag surface=grass.
Do others agree with me that roughs should indeed be mapped according to golf play areas, not grass length? I think this is the most elegant way to address the issue, but am certainly open to suggestions.
This is a known issue. Unfortunately, this can’t really be solved until the relevant data consumers (i.e. TGC-Designer-Tools) follow the OSM guidelines. Mappers should be aware that their activity amounts to Tagging for the renderer - OpenStreetMap Wiki.
I’m not sure where the difference is to the current definition. Can you provide a specific example?
I wanted to provide more examples in my initial post, but was limited to 3 links.
There are three St Andrews courses practically neighbouring each other demonstrating what I mean:
The St Andrews Castle Course has most of the areas mapped as roughs, including the area between the tee box and the fairway. Golf paths are marked on top of it as paths mapped using tagged lines.
The Fairmont’s Torrance Course has some paths, but also some very straight lines mapped as the rough running across the course. These lines are not connecting a tee to a fairway, but are similar cuts of grass because it’s a path or an area around a wall in this case.
The Kingsbarns Golf Links only have the rough first cut mapped as the rough, not the second cut or to the actual OOB line. Paths are mapped solely as a line and sometimes using the surface=grass value to indicate the fact that it is indeed grass.
When looking at these, I thought some more similarity between courses would be nice. From the wiki page I expect that the Castle Course is best, Kingsbarns might be OK and that the Torrance course is wrong. But the wiki article is not explicit enough to confirm this. My first stab at a revised definition is to answer that question.
If the golf=rough wiki article is revised with good/acceptable and bad examples, hopefully there’ll be a bit less variation in mapping practices. After all, this is a community effort so it’ll never be exactly the same with every mapper.