New methods, algorithms, and software for rapid mapping of tree positions in coordinate forest plots
The theories and methodologies for two new tree mapping methods, the Sequential-target method and the Plot-origin radial method, are described. The methods accommodate the use of any conventional distance measuring device and compass to collect horizontal distance and azimuth data between source or reference positions (origins) and target trees. Conversion equations are presented to convert field-derived azimuth coordinates to plot-center coordinates, permitting plots of all tree positions relative to the geometric center of the plot. Plot rotation algorithms for Polar X and Polar Y plotting methods allow the rotation of all plotted positions to any orientation within a rectangular mapping frame and permit corrections for magnetic declination. Additional algorithms are provided to calculate horizontal distance and azimuth between plotted trees and plot-center or between any two tree positions in the plot. All algorithms were incorporated into TreeMapper, a computer program for DOS. The methods and software were tested on a forested plot. Low mean differences between actual and calculated values indicated the accuracy of the methods. The mapping methods and software, originally developed to map trees in research plots for spatial and epidemiological studies of oak wilt disease, have wide applications in forest inventory, management, ecology, spatial-modeling, and other field activities and tasks that require accurate information about tree positions and spatial distribution patterns and ways to keep track of tree attributes and treatments over time. More detailed explanations of the methodologies for downloading data and running TreeMapper will be provided in a second paper.