Help! Missing Land Mass

Hi!

Can someone either advise or fix what I am referring to as a missing land mass. The place is called Davaar Island and is located at the following coordinates within the UK.

Davaar Island Trig Point

NR 75775 19989

55 25’20.47N 005 32’41.28W

The island is a local tourist attraction with a painting of the Crucifixion on a cave wall, apparently discovered in the 1890’s by a drunk sailor.

Any help will be greatly appreciated.

Normally I’d start by going to https://www.openstreetmap.org/ and selecting “help” there. That’ll take you to https://www.openstreetmap.org/help - the “welcome” link will show you a short introduction (including to make sure that the information that you want to add isn’t from a copyright source). Down the bottom of that page there is a “start mapping” button.

In your case however searching OSM for “Davaar Island” finds https://www.openstreetmap.org/way/104809516/history , so it’s already been added, but it looks like someone’s forgotten to exclude it from the Firth of Clyde. I’ve mentioned that at https://www.openstreetmap.org/changeset/71238687 .

Best Regards,

Andy

The island is there without natural=coastline (the better drawn outline). A coarser outline is there drawn to almost duplicate the island it was tagged only natural=coastline. I’ve removed the coarse outline and then tagged the island outline as natural=coastline. It already starts to render but could take a while to appear at all zoom levels. Changeset 73256240 in case I’ve messed up.

I’m not seeing it at https://a.tile.openstreetmap.org/19/254064/164744.png/status etc. I suspect the massive water polygon will need it adding as an inner too.

According to the changeset discussion this was done about an hour ago. So now it should really start to render some time in the future ;-).

Yes - that change has fixed https://map.atownsend.org.uk/maps/map/map.html#zoom=15&lat=55.42471&lon=-5.54441 (which uses the old style way of rendering land and water not the new OSM-Carto way). The main site will follow along shortly I suspect.

Hi!

I would like to thank all of you that replied to query. Currently nothing has changed but I will wait and see what happens.

Best regards
Russ

Maybe the overlapping inners at https://www.openstreetmap.org/relation/9687049#map=19/55.42478/-5.55289 is the problem?

See https://www.openstreetmap.org/way/592472943 and https://www.openstreetmap.org/way/104809516 - someone edited that just 8 minutes ago, so things may change soon…

The island and the shingle area were marked as outers in the Firth of Clyde relation, I marked them as inners today. I don’t think this will help with the rendering though.

The shingle area and Davaar Island are intersecting (nodes not connected) and the shingle area is creating duplicate segments on both ends (coastline is outer and shingle is now inner). The Firth of Clyde-relation is throwing errors.

Some thoughts:

I was wondering if the shingle area is actually flooded regularly/low-tide only? Maxar/Esri/Bing make it look that way.
If so, does it actually need to be excluded from the Firth of Clyde-relation as it seems to be tidal? I would probably think of it as natural=shoal this way. Maybe natural=shoal + surface=gravel is the more appropriate tagging (and also rendered in water if that is a concern)

Without it the relation would be fine.

HI!

The shingle is tidal! It is completely covered at high tide!

Regards
Russ

Just to note The Dorlin or shingle is starting to render on the main map, up to the point where it connects to the island.

Regards
Russ

HI!

As an update to my previous plea for help which I have attached below, the island (Davaar Island) has now rendered but the shingle tidal walkway which rendered previously has now disappeared. I have tried to fix this myself but I do not have enough knowledge to correct this.

Can anyone help or advise please.

I’m not the expert you might be looking for, but this looks like a useful comment:

as does this:

Further, or perhaps further detail on the above:

It looks like there are two objects, called The Dorlin and The Doirlin, both natural=shingle, and perhaps they’re competing/interfering with each other.

One is a relation: https://www.openstreetmap.org/relation/9959264
Other is a way forming part of that relation: https://www.openstreetmap.org/way/722058485

I’m not sure you need a relation if the shingle is one simple area (although its ways may form part of other relations, such as the Firth of Clyde).

Quite possibly you did mean this for some reason - you edited both together in one changeset the other day - but thought I’d mention in case it’s relevant.

Hi!

I duplicated The Dorlin as a enclosed area to see if that would help. It was originally it was an enclosed area and it did render while the Island did not then someone disconnected the ends and the The Dorlin disappeared and the Island rendered. I will go in and delete the area I enclosed as its not working anyway. I just don’t enough about OSM yet to fully know what I am doing. Hence I’m looking for help or advice. Thanks for your time. Regards

Well I’ve been dithering about with the map for a while now, and I still can’t get multipolygon relations right without assistance. It’s the trickiest bit of mapping I’ve come across, so I avoid whenever I can. Unless I’m misunderstanding your problem here, I think you could do without a relation altogether for the Dorlin itself: you’re not in the position of needing to ‘cut a hole’ out of an area of the Dorlin where different properties apply.

However, the Firth does need a Davaar Island-shaped hole cut out of it (ie, Firth relation includes the island boundary as role=inner). It may also need a Dorlin-shaped hole (ie, the Dorlin area is also listed in the relation as role=inner), depending on how tidal areas are treated, which I don’t know.

Dunno how much this is helping!

PS, there is quite a bit of noise going on on the Firth relation there:

See how most of it is a single red line around the coast, but there are multiple overlapping lines on the Dorlin:
Dropbox link

Regardless of the rendering, it seems to me that spaghetti should be tidied up - who knows, your rendering problem may then magically disappear.

Hi, Just by chance I had a look here yesterday and removed the one and only overlap from the area. It was one single node of Way: 717613611 projecting over the shingle area, I don’t think it should have caused problems.

This morning I notice that the shingle inner touches the outer of the multipolygon relation. I’ve amended it si the shingle inner doesn’t touch the Doirlin outer. Maybe this will fix it. It’s Changeset: 74198490 if it needs to be reversed

Shingle still seems not to be rendering. Is it possibly the tidal tag, rendering it underwater? Or, I notice there’s a mismatch between the tags of the wetland and the shingle: wetland has more tags (working together, it seems) and possibly some of these are needed on the shingle, too?

A similar situation is here: https://www.openstreetmap.org/way/491657992 or http://map.openseamap.org/?zoom=17&lat=51.39211&lon=3.42444&layers=BFTFFFFFFTF0TFFFFFFFFF
Just the parts above the groynes are pitch-green. In the past (a month ago, or so) the whole area was green.
This is/was for kite areas at sea, the kitesurfing areas in inland waters were/are not rendered at all.
So I assume this fails due the render rules.