Positioning of coordinates and precision analysis of sample trees using the intelligent forest survey calculator

摘要

Sample trees have great significance for extracting forest parameters and realizing well-targeted forestry operations. Accordingly, determining the precise position and coordinates of the sample trees is of special importance. In this paper, a new type of portable electronic instrument with high precision, the Intelligent Forest Survey Calculator (IFSC), is introduced. For the instrument, we have developed guidelines and explained the principles and methods for surveying locations of sample trees in fixed plots during forest survey. The instrument was set up at a starting site near the center of a fixed sample plot, and different sites were observed according to the distribution and density of sample trees. The instrument can also determine the coordinates of the sample trees using an integrated angle and distance measurement device on the basis of Bluetooth Low Energy (BLE) data transfer. The measurement precision influenced by both the stability of the instrument and environmental changes within the investigated area. To verify and analyze the interior and exterior adherence accuracy of the 3D coordinates produced by the IFSC, we conducted experments on 20 x 20 m fixed plots in Beijing Songshan National Nature Reserve. The errors of planar positioning (X and Y directions) were 0.0572 and 0.0561 m respectively, and the error of height (Z direction) was 0.0643 m. Our data therefore demonstrate that the IFSC has high precision in measuring the position coordinates of the sample trees, and can provide accurate data that can meet the requirements of practical forest surveys.