**Author details**

Lingli Zhu<sup>1</sup> \*, Juha Suomalainen<sup>1</sup> , Jingbin Liu1,3, Juha Hyyppä<sup>1</sup> , Harri Kaartinen<sup>1</sup> and Henrik Haggren<sup>2</sup>

\*Address all correspondence to: lingli.zhu@nls.fi

1 Finnish Geospatial Research Institute FGI, National Land Survey of Finland, Masala, Finland

2 Aalto University School of Engineering, Aalto, Finland

3 Wuhan University, Wuhan, China
