Woah, lots of work getting done in this area. I did notice there is a community that has their backyards digitized with natural features. Very uncommon to see when editing.

Thank you for sharing this.

I only had time to skim through but I really like the comparison and the details provided on the blog post.

This would be an awesome edition to openstreetmap.

However there might be many reasons why this is unlikely to be added. 1. Imagery 2. Downloadability.

There are tools that make mapping easier in malls and on the go mapping. Maybe this type of tool would be effective in aiding efforts to map underground, although these apps require GPS functionality.

Definitely if this is something you want to start working on and pushing for. GO FOR IT.

House