Hello, first set of edits, and first question.

I'm using JOSM as I couldn't get Potlatch to run.

I have a school who's grounds extend into into some woods, the school fence runs through the woods, and it has some outdoor classrooms and woodland trails inside those fenced off parts of the woods. The rest of the woods are common and people can walk anywhere, but the school fence denotes private land. So it seems to me the ideal would be to be able to draw the woodlands and the school overlapping. However when I do that, one or the other is displayed on top, and the other is not visible underneath. Is there some way to do this?

If not, what is the best/standard way to represent it?

EDIT: I didn't want to swamp this question, so I would like to recommend that people read all the answers below, it's very interesting.

asked 20 Apr '12, 18:20

skanky's gravatar image

accept rate: 0%

edited 23 Apr '12, 17:55

Thanks to everyone for their responses.

When I looked into fixing this bit of the map, I had thought that there was one, definitive answer as this must be a fairly common situation. It looks like I leapt into the deep end for a first edit as there seems to be a number of approaches and none of them necessarily correct. However it's been instructive in that I can see the merits of all the above answers and though I'm forming an opinion as to which I think may be best I can understand that that's just my opinion and as I'm very inexperienced, I'll leave this as it is for now (apart from fixing the gardens in the SE corner). Maybe I'll revisit later or see if anyone else does - but that may depend on if I see issues with renderers other than the website.

The issue was compounded by one or two other "errors" or inconsistencies (some of which were probably mine). So there's been some education aside from the main question.

Hopefully this will provide help for anyone looking into this issue in the future, even if it's not as simple as they hoped. :-)

(23 Apr '12, 17:53) skanky

I suggest to have the wood end at the fence and then draw another wood area inside the school's area.

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answered 20 Apr '12, 19:51

TheOddOne2's gravatar image

accept rate: 3%

Won't that just give the same problem?

Sorry I didn't explain very well.

The school grounds extend into the woods and they both share some borders.

The school and wood are here: http://www.openstreetmap.org/?lat=53.3374187350273&lon=-1.4866116642952&zoom=17

I have to admit that I have edited this, and was only aware of the issue when I saw the final result in the browser. The woods used to be visible. I could revert it, but I do think that the fact that the school extends into the woods should be marked.

Could I put a separated marker through the woods and tag it?

(20 Apr '12, 22:30) skanky

Let the woods outside the fence be one area (closed way) end it outside the fence/school, if you want, you can let it share nodes with it. Draw a new area within the school's area (you can let it share nodes as well). Sorry, can't really explain better than that. It won't give the same problem otherwise I wouldn't suggest it.

(20 Apr '12, 22:47) TheOddOne2
(20 Apr '12, 22:59) TheOddOne2

Okay thank you. I'll try it when I'm back online.

(21 Apr '12, 08:43) skanky

Thanks again, and sorry I doubted your suggestion without trying it. :)

I think that's good enough for now. Seems to make sense on the map. Any comments welcome - if anyone does update/fix it based on this question, can they post here to say what they've done, please.

(21 Apr '12, 21:26) skanky

On the general point of "feature X overlaps feature Y" I wouldn't worry about it. If on the ground X really does overlap Y, then that's how I'd edit the data.

However, where there are different tags that apply to the part of the wood in the school grounds compared to the other part (perhaps an access tag?), then it does make sense to split it.

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answered 20 Apr '12, 23:16

SomeoneElse's gravatar image

SomeoneElse ♦
accept rate: 15%

Okay thanks. It's just that the render of school obscures the woods. I did wonder about making a third area that shows the overlap and tagging it accordingly. But I'll try the other answer first. On phoneat the moment, so will get to it later.

(21 Apr '12, 08:42) skanky

There are lots of different renderers - the "Standard" view on the OSM website is just one of them. Generally speaking it does an excellent job of showing lots of different sorts of data, but it can't show everything on top of everything else. A map that concentrates on showing wooded areas would get it "correct", as would one that concentrates on schools.

(21 Apr '12, 12:17) SomeoneElse ♦

Thanks for the info. I did wonder if some renderers would get it right, but (a) wondered if there was a way to get the OSM website showing it right and (b) wanted to know if there was a correct way to do this - I couldn't find anything discussing it. It's been an interesting and informative exercise so far...

(21 Apr '12, 20:22) skanky

I would

  1. create an area that delimits the school property, add the Tag:barrier=fence, if any, as hinted by (13 hours ago) TheOddOne2 and add a new relation (advanced, multipolygon) to this area with the role "outer" and save to get a relation number
  2. create a forest area within a few pixels inside the school property area and add the previously created area with the role "inner"
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answered 21 Apr '12, 12:59

gerdami's gravatar image

accept rate: 15%

edited 21 Apr '12, 13:02

Thanks for the answer. I didn't quite understand it, and the earlier one worked. Once I'm a bit more experienced, I might revisit this and see if that's a better solution, but for now TheOddOne2's has worked.

(21 Apr '12, 21:24) skanky

Hello, one thing not mentioned is that both the school and the woods in the school area are on top of an area tagged residential. I think the first thing to do is remove that residential area that the school takes up, this will remove one unnecessary layer from the problem. I think it is the layering of areas that is causing the problem. I would keep the woods as they are, (an area in their own right,). Then make the area that the school building is in a multipolygon within which (as an inner cutout) is the school building. The areas are then separated, do not overlap, but can where appropriate share nodes.

Another point if you don't mind me saying, you have the school named on both the building and the area, this means the name is rendered twice. The areas name tag has been rendered half in the woods. The buildings name tag is rendered on the school building which looks best appropriate.

Last thing when the Bing Arial image, (capture date 4/22/2011) is viewed the gardens seem to protrude into the schools wooded area at the south east corner. I'd just politely query if this is now part of the school. Regards

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answered 22 Apr '12, 19:44

BCNorwich's gravatar image

accept rate: 21%

Thanks for the reply, I'll answer the points separately (will take two comments):

1) Most of this was already here and I was looking to update due to the changes to the school, and fix some errors in the paths etc. The residential area was already there, and I didn't want to mess with the map too much as it's my first edit. I may revisit though.

2) I'm not sure I fully understand your suggestion as to what to do. I'll do some reading and have another look when I get a chance though. Thanks.

(22 Apr '12, 20:17) skanky

3) The school area may have gained a label as a side-effect of my edit, but I think it already had it. I'll address that.

4) The gardens bit is probably an error on my part, thanks. However you'll notice elsewhere that there are buildings that don't line up properly. Should they be fixed? I'll re-read the imagery stuff on the wiki again.

(22 Apr '12, 20:20) skanky

The school building is part of the school, so it is incorrect to map it as the inner part of a multipolygon.

Also, as skanky described it, part of the woods are within the school grounds. So they should be within the outline of the area tagged as amenity=school.

(23 Apr '12, 15:40) Vclaw

Hello, I didn't realise it was your first edit, I found this very intimidating at first. It is not easy unravelling situations like this, (ways/nodes have to be disentangled, (unglued)) then redrawn. I did test most of my suggestions and they do look better, would you like me to have a go at sorting it out later today, work gets in the way right now? Regards Bernard

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answered 23 Apr '12, 07:41

BCNorwich's gravatar image

accept rate: 21%

edited 23 Apr '12, 07:42

Thanks for the offer. I can't get to do it until this evening, so if you do and want to have a go, please do. Obviously I'll update before I try, so I won't trash anything of yours.

I did look at the SE corner, and I think I've sorted that out, but not uploaded yet. Don't worry about that though, as I may have messed up the interaction with the woodland there (I can tweak the border afterwards though as I can check it on the ground). Looking, I think that error was there before my edits though it could easily be mine.

Thanks again.

(23 Apr '12, 09:01) skanky

Hi skanky, That's all areas done, have a look and see what you think.

(23 Apr '12, 14:31) BCNorwich

Hi BCNorwich, thanks for that. It looks good but I'll need to tweak the area round the gardens - it's not obvious from the imagery exactly where those gardens extend to as there are trees in the gardens. Also there are trees in the school grounds next to the gardens.

The only issue (if it is one) with the woods and the school area not overlapping is that that's what they do on the ground. Would it look more ambiguous on a different renderer?

(23 Apr '12, 17:43) skanky

You have now to close way 23113160 to make the bigger wood reappear ;-)

(25 Apr '12, 11:39) gerdami

Now closed, thanks gerdami. skanky I've made the school woods as within the school total area. It just leaves the gardens that seem to protrude into the school area and the woods line south of Harbod Road where the houses are half in the woods, that needs you to survey it.

(25 Apr '12, 13:29) BCNorwich

Thank you.

Done. It's probably not perfect as it's difficult to see exactly where everything ends in the wood - but that's certainly better than it was. Also, I removed the fence and made the whole school area as bounded by a fence, as that's what it is.

EDIT: Actually there's a few bits around the school that need another look, but as the main question has been resolved, I can fix those when I've checked them out.

Finally, I tidied up/fixed a few other issues (missing house, etc.) that I've noticed over the last few days, at the same time.

(25 Apr '12, 21:48) skanky
showing 5 of 6 show 1 more comments

Maybe we should raise a rendering issue that an area extending into natural:wood or landuse:forest should be tainted light green.

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answered 15 Jun '12, 20:57

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question asked: 20 Apr '12, 18:20

question was seen: 5,444 times

last updated: 15 Jun '12, 20:57

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