Comparison of Three-Dimensional Green Quantity of Campus Trees Based on 3D Laser Point Cloud Data—A Case Study of Guangxi Eco-engineering Vocational and Technical College
The crown of a tree refers to the part above the trunk along with its branches and leaves,and its volume is an important parameter for estimating the three-dimensional green volume of a tree.The canopy morphology of trees in campus green spaces is diverse and the structure is complex.Accurate,automatic,and non-destructive measurement of tree canopy volume is an important research project in campus green space investigation.A com-parative study was conducted between the three-dimensional laser point cloud data of 25 trees from 5 randomly selected tree species and the three-dimensional green quantity crown width crown height formula method of trees.The 3D laser point cloud data obtained from a 3D laser scanner is used to calculate the volume of tree canopy based on the irregular triangulation method.The comparison of calculation results shows that the root mean square error(RMSE)between the measured value and the reference value is 2.913,with a maximum absolute error of 7.22 m3 and a minimum error of 0.17 m3;The maximum relative error is 11.06％,and the minimum value is 0.12％;The average absolute error is 2.20 m3,and the average relative error is 3.13％.This algorithm does not need to consider the shape of the tree crown,reducing the differences caused by human discrimination.Therefore,using a 3D laser scanner to obtain point cloud data and using irregular triangulation to automatically extract the volume of tree canopies in campus green spaces is fast,effective,and scalable.
three dimensional green quantity of treescrown volumethree-dimensional laser point clouduniver-sity campus green space
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