1. Context

Lidar, an acronym for light detection and ranging, is an active laser-pulse remote sensing technique used in the atmospheric and terrestrial domains. On land, it is used in particular for three-dimensional topographic surveys of natural or built-up surfaces. It provides a precise description of these surfaces in the form of a georeferenced point cloud. There are two main modes of acquisition:

• or by a terrestrial station (TLS – terrestrial laser scanning );

• or an airborne laser scanning (ALS) system.

This article will focus on airborne systems for topographic applications.

These applications cover a wide range of fields: geology, seismology, public works, natural hazard monitoring, as well as archaeology, where lidar is used to detect and map sites...