Visual The effectiveness of combining TOF and TLS point clouds in measuring the quantitative characteristics of urban trees

Depending on the purpose, different species of broadleaf and coniferous trees are used in the urban green space, which has diverse and complex characteristics. In this study, to obtain accurate information about trees and to cover the weaknesses of two technologies, TLS and TOF, their combination was used. For this purpose, 20 trees were selected from broadleaf (Fraxinus Ornus L. & Ulmus umbraculifera) and coniferous (Cupressus sempervirens L. & Cupressus arizonica Greene) species in the green space of Khajeh Nasir Toosi University and their point clouds were produced using TLS and TOF. After processing point clouds, the parameters of breast diameter, basal area, and crown area were measured. The RMSE of measuring the diameter at the breast of broadleaf and coniferous trees using TOF technology was 0.33 and 0.38 cm and TLS technology was 0.59 and 0.62 cm respectively. The diameter measurement error of the broadleaf is less than the coniferous due to the thinner bark. The basal area measured using TOF technology is more accurate than TLS; On the other hand, TLS technology has a precise and unique function in measuring the crown area. The basal area and crown area of broadleaf trees showed more errors than coniferous trees due to the asymmetric and irregular shape of the stem and crown. According to the obtained results and the examination of the strengths and weaknesses of these technologies, the combination of these two leads to more accurate and comprehensive results. Therefore, it is recommended to use the integration of these technologies in detailed scientific studies that are the basis of executive works.