DO NOT PLACE COASTLINES INSIDE RIVERS! You will end up “flooding” the whole place.
That’s the main point.
To make islands in inland bodies of water, you need to create multipolygon relations. These are very hard to explain to a new user, but the official introduction to them is here (on OSM site: osm.wiki/Relation:multipolygon). If you google something like “osm multipolygon river island” you can find some people trying to explain how it’s done, too, along with more official documentation here: osm.wiki/Rivers.
In fact, when I was new to OGF, none of this was very helpful - it seems quite complicated and impractical.
The best way to learn how to draw things like multipolygon rivers with islands is to find successful examples on the map, and open them up in edit mode and study how they’re put together - but don’t edit them! Just look at them!
Here is an example of a river I made a year or two ago in Commonia, which is surprisingly unbroken still:
So you can zoom in with iD and study it and the islands carefully - how are they tagged, what features do they have? Really that’s the only way to learn.
You made a good effort, but didn’t quite fix it. I have dropped a single change on your river/island, and it should render properly now.
Key idea:
You have two “circles”. The outside circle is the riverbank, the inside circle is the island. Like a donut.
Both of them are “members” of the same relation. The outside circle gets “role” = “outer” and the the inside circle gets “role” = “inner”. Then you can add more islands, with more “inner” .
I learned making relations via this site. It explains things so simpel even I (stuck on Potlatch for most of my editing) could do it easily. Just follow the example with the building and you’re there.
OpenGeofiction
Discussion
Comment from Luciano on 17 September 2017 at 22:51
DO NOT PLACE COASTLINES INSIDE RIVERS! You will end up “flooding” the whole place.
That’s the main point.
To make islands in inland bodies of water, you need to create multipolygon relations. These are very hard to explain to a new user, but the official introduction to them is here (on OSM site: osm.wiki/Relation:multipolygon). If you google something like “osm multipolygon river island” you can find some people trying to explain how it’s done, too, along with more official documentation here: osm.wiki/Rivers.
In fact, when I was new to OGF, none of this was very helpful - it seems quite complicated and impractical.
The best way to learn how to draw things like multipolygon rivers with islands is to find successful examples on the map, and open them up in edit mode and study how they’re put together - but don’t edit them! Just look at them!
Here is an example of a river I made a year or two ago in Commonia, which is surprisingly unbroken still:
http://opengeofiction.net/#map=15/-2.5901/142.4430
So you can zoom in with iD and study it and the islands carefully - how are they tagged, what features do they have? Really that’s the only way to learn.
Comment from MCRoads on 17 September 2017 at 23:49
THANK YOU!! you have no idea the headache i had trying to “un-flood” the island.
Comment from Luciano on 18 September 2017 at 00:07
You made a good effort, but didn’t quite fix it. I have dropped a single change on your river/island, and it should render properly now.
Key idea:
You have two “circles”. The outside circle is the riverbank, the inside circle is the island. Like a donut.
Both of them are “members” of the same relation. The outside circle gets “role” = “outer” and the the inside circle gets “role” = “inner”. Then you can add more islands, with more “inner” .
Hope that helps.
Comment from Marcello on 18 September 2017 at 19:34
The ‘net is your friend.
http://learnosm.org/en/josm/josm-relations/
I learned making relations via this site. It explains things so simpel even I (stuck on Potlatch for most of my editing) could do it easily. Just follow the example with the building and you’re there.
good luck !
Marcello.