Operation suggestion: cut off / cut out for splitting areas

[joepie91]

Something I've run into a couple of times now, is the desire to split an area into multiple parts; because a part of a park was repurposed, because two halves of a parking terrain had different access rules, and so on. I don't seem to be the only one either (eg. #6988).

I feel like this class of usecases could be addressed generically through the addition of two new operations to the operations menu that are very similar to each other, which I'd therefore like to propose:

• Cut off: Displayed when both an area and an unclosed polygon are selected. Selectable when the polygon fully crosses the area. This would cut the area into two parts, across the drawn polygon.
• Cut out: Displayed when both an area and a closed polygon are selected. Selectable when the polygon overlaps the area; it does not need to be fully enclosed within it. This would "cut out" the specified shape from the area, making it its own area.

In both cases, the new area would initially have the tags of the 'existing area' copied into it as-is; this means that when splitting an area to apply a subtle change (eg. differing parking access, connected houses with just a different street number), all the remaining metadata is retained and does not need to be re-entered.

This approach would not require redrawing any areas, thereby avoiding potential loss of precision in doing so. It would also use the existing drawing primitives for specifying the splitting boundaries instead of introducing new UI, reducing implementation complexity and keeping the UI simple.

The process illustrated, where red lines signify the line segments / polygons used to determine the split position, and the numbers indicate the resulting area features:

Thoughts?

[UgnilJoZ]

I share your desire to cut areas in a more-controllable way.

I would prefer a context menu option (analog to line-cutting) which prompts you to draw a line within the area (same UI as drawing a way). Whenever your line divides the area into two parts, the area is divided and the line disappears.

This would cover both use cases: cuttting off and cutting out.

[k-yle]

"Cut out" is already supported, if the inner area is completely within the outer area:

1. Draw the outer and the inner area
2. hold down Shift and select both areas
3. then press C