Drawing lakes.

I’ve got some contour of one big lake, but really i need to divide it into smaller ones (with different names). I have tried to add ways with natural=water to existing multipolygon, but it makes them not to render. I’m also interested in the way which i could clone already existing path without making new nodes, so i could connect few of them into that smaller lakes. I’m using JOSM. Sorry for my english.


welcome to the forum. Your English is fine.

I assume you talk about relation 1113101. Your changesets are few enough to figure it out. There’s a similar example Thailand Songkhla: Thale Songkhla Sap. To study it in JOSM you can download the area with this link or just download the three multipolygon relations 1116318, 1116319 and 1116383 to be not distracted by other objects.

The three lakes are adjacent to each other. Each of them is described by a separate multipolygon. The common borders consist only of one line. With multipolygons it’s not necessary to have duplicate lines on top of each other. The outer lines of the lakes consist of multiple ways and don’t have any tags. The tags are at the relations. The islands are inner elements and are tagged.

The steps to modify your lake could be:

  • For each new lake create a relation type=multipolygon and tag them accordingly.

  • Remove the tags from the current outline of the big lake.

  • Split it at the appropriate points in smaller way segments.

  • Draw new lines as borders between the lakes. Delete the duplicate lines which are there already.

  • Add the outer members (shores of the lakes) and the inner members (islands) to the multipolygon relations.

To help understanding the situation and to give dedicated advice it would be great if you could post a permalink in the future as I did. It is on the map in the bottom right corner. You can also post the id of a way or relation which you can lookup in JOSM.

Don’t hesitate to ask again if you have further questions or want someone to look at it.