How to map, where to base a slanted retaining wall line?

[Mammi71 (One feature, Six mappers and still More ways to map it)]

As with embankment, I would take the top edge for the line. What is missing is a definition of the base point.

The problem is basically the same as with embankments:

Mapping embankments

The Dutch community is discussing better/additional mapping for embankments. Since Nederland has over 17K kilometers of dykes to hold the water out and in place, plus a lot of embankments to carry railways and roads, embankments really define the landscape in large parts of the country. Currently embankments are mapped as a crest line only, tagged man_made=embankment. Some mappers also map the toe line as man_made=embankment. I am thinking of proposing a tag for a way representing the toe line…