Geography Reference
In-Depth Information
Creation of the Accurate Raster Driven
Polygonal Environment for the 3D Surface
Models Based on the LIDAR Technology
Jan Hovad and Jitka Komarkova
Introduction
Light detection and ranging (LIDAR) is a frequently used technology that provides
information about elevation of scanned objects, their position, classification etc.
Laser-based ranging instrument measures distance (range). The basic principle of
the measurement is simple. The measurement is based on the precise measurement
of time. Intense laser pulse is transmitted from instrument to the object; it is
reflected from the object and detected by the instrument. Elapsed time period is
measured. Range is calculated, based on the knowledge of the speed of light.
Alternatively, the laser transmits a continuous beam. In this case, transmitted and
received sinusoidal wave patterns are compared to obtain the slat range. LIDAR
allows to collect explicit elevation (3D) data at a very high accuracy. Simulta-
neously, LIDAR scanning produces data in large volumes (Shan and Toth
2008
).
Authors use raw LIDAR scans as inputs to create final photorealistic 3D polygonal
surface models.
Creation of the digital terrain model (DTM) is frequently discussed topic and it
can be evaluated in the detail from authors like Kraus and Pfeifer (
2001
). DTM
serves as the ground for the surface objects. Its creation and precision is dependent
on the used algorithm. These approaches can be further studied from authors like
Hu (
2003
) and Elmquist (
2002
). None of the approaches are suitable for the
intended result. Authors propose to use slope based polygonal terrain model system.
Vegetation modelling, e.g. placement of trees in the space and identification of
their height, belongs to the most important parts of this article. Klimanek (
2006
),
Omasa et al. (
2008
) deeply dealt with this topic. The main idea is to use the laser
