COMPARISON OF GRASS-LIDAR MODULES AND TERRASCAN IN GROUND AND VEGETATION FILTERING
The work presents the comparison of results obtained with two different methods for filtering LiDAR data, focusing specifically on ground (bare Earth) and vegetation classification.
Data was filtered with TerraScan, a leading proprietary software for processing LiDAR point clouds, and with the specific modules available in GRASS GIS.
Concerning TerraScan two classifications were computed: the former is a completely automatic and the latter is a semi-automatic one, with a heavy manual reclassification of the previously obtained automatic results.
In GRASS GIS the modules developed by the Geomatic Laboratory of the Politecnico di Milano were applied; parameters to be used by the modules were at first calibrated on specific training sub-areas.
The LiDAR dataset (1,5 points/m2) was produced with an Optech ALTM Gemini and covers an area of the
The purpose of the work is the evaluation of the accuracy in ground and vegetation extraction. Moreover since GRASS divides points belonging to vegetation in two classes, corresponding to high e low vegetation, the comparison is done for these two categories.
As “ground truth” the result of the supervised classification performed on the orthophotos and the false color infrared images was used.
Sara Lucca - Politecnico di Milano - Polo di Como
Maria Antonia Brovelli - Politecnico di Milano - Polo di Como