Personally I would just draw the new polygon inside the area not touching the existing lake outline, then drag the points close to the lake edge and call it a day. Having them be joined together can be a pain especially on a large entity or relation like a lake.
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Draw it as a polygon, not a line.
Ideally you do go over the points of the shoreline, but if you skip some and the forest doesn't overlap with the lake that's a good start, it can be refined later.
I suspect you're only creating a line/way, not an area/polygon/closed way.
The first node/point you create/use must also be the last node you click. 1, 2, 3, 1.
well i difenetley do not want to draw polygon \ area because i would need to go by clicking lake coast points wich are a lot of points with crazy geometry and then only get it to forest area
Well that's how you make a polygon in iD.
You don't actually need perfect geometry on your first pass of an area like this. There is basically no existing data, so you aren't damaging good data. You can add a massive overlapping polygon which gets cleaned up over time.
What they are suggesting is certainly possible. A segment can be shared between two different relations.
The process would be: 1) Draw the line around the boundary of the forest, connecting the endpoints to points on the lake. 2) Split the way that is part of the lake at the two endpoints of that new line. 3) Select each way you want to be in the new multipolygon and create a new relation.
Doing this makes it so that there is a single way with two relations on it, instead of two ways (each with a single relation) that share a bunch of points.
Yeah, i do this way always , but maybe i don't get write it correct in English (not my born language) Let me try to change a chapter:
The way you described used by me all the time, line touches polygon in two points where it can be cutted and worked on forward very well (anyway thanks!)
But, if you draw a line that touches multypolygon - cut tool ain't works in places it touches multypolygon (not allowed - showed as gray)
You may have to download the the data for the whole lake. Select the way you want to split. Under relations you should see Lake Алла-Аккаярви and to the right a download button, a delete button, and button with a square and a dot in the center that highlights the whole lake. Just press the download button and you should be able to split it.
Thanks , i will try it 👍
if i delete dependencies from lake-coast (wich is multypolygon by itself)
You shouldn't need to delete anything. I am not sure, but it seems like you are deleting the members of the relation, those definitely need to stay.
