Using UAS-Based Point Clouds to Generate High Resolution Digital Terrain Model for Forestry Research and Applications*

Year 2016, Volume: 2 Issue: 1, 35 - 40, 19.11.2016

Cigdem Serifoglu Yilmaz Volkan Yilmaz , Oguz Gungor

Abstract

Digital Terrain Models (DTMs) as well as Digital
Surface Models (DSMs) have been widely used in many forestry applications,
especially in locating forest roads, developing transportation planning, and
determining the stand parameters. Generally, LiDAR (Light Detection and
Ranging) point clouds have been used to generate DTMs, since LiDAR technology
is able to provide multiple returns, which is very useful to separate the
ground surface and non-ground objects such as trees, buildings etc. However,
LiDAR technology generally requires a high cost and this, of course, has a
negative effect on the use of LiDAR point clouds. In this study, the DTM of a
study area was generated by means of the point cloud extracted from the aerial
images taken from a UAS (Unmanned Aerial System). As the first step, the
UAS-based point cloud was filtered to separate the points belong to the ground
and non-ground objects. Thereafter, the filtered point cloud was interpolated
to obtain the DTM of the study area. Finally, field measurements were conducted
by using Real-Time Kinematic GPS (Global Positioning Systems) measurement
technique to evaluate the accuracy of the produced DTM. Multiquadratic CRC, CP
and CHTS surfaces were used as Q surfaces. Bi-linear surface was chosen as the
trend surface when conducting the Multiquadratic interpolation algorithm.
Accuracy evaluations revealed that it is possible to generate high-resolution
DTMs by using UAS-based point clouds. The results indicated that the CRC and
CHTS algorithms provided better results in representing the topography,
compared to the CP algorithm.       

Keywords

Unmanned Aerial System, Digital Terrain Model, Forestry, Point Clouds, Ground Filtering

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