useful commands:
- distance/measuregeom
- zoom ext
- line
- trim / extend
- offset
- "signature": sketch
- donut
- xline: for coordinate axis (infinite lines)

- f8: perpendicular
- f2: console

questions:
- differences in LKS94?
  -  https://epsg.io/3346
  -  https://epsg.io/4669
  -  https://epsg.io/4951
  -  https://epsg.io/4950