INTERPNT Software for Mapping Trees Using Distance Measurements

The INTERPNT method can be used to produce accurate maps of trees based solely on tree diameter and tree-to-tree distance measurements. For additional details on the technique please see the published paper (Boose, E. R., E. F. Boose and A. L. Lezberg. 1998. A practical method for mapping trees using distance measurements. Ecology 79: 819-827). Additional information is contained in the documentation that accompanies the program. The Abstract from the paper is reproduced below. "Accurate maps of the locations of trees are useful for many ecological studies but are often difficult to obtain with traditional surveying methods because the trees hinder line of sight measurements. An alternative method, inspired by earlier work of F. Rohlf and J. Archie, is presented. This "Interpoint method" is based solely on tree diameter and tree-to-tree distance measurements. A computer performs the necessary triangulation and detects gross errors. The Interpoint method was used to map trees in seven long-term study plots at the Harvard Forest, ranging from 0.25 ha (200 trees) to 0.80 ha (889 trees). The question of accumulation of error was addressed though a computer simulation designed to model field conditions as closely as possible. The simulation showed that the technique is highly accurate and that errors accumulate quite slowly if measurements are made with reasonable care (e.g., average predicted location errors after 1,000 trees and after 10,000 trees were 9 cm and 15 cm, respectively, for measurement errors comparable to field conditions; similar values were obtained in an independent survey of one of the field plots). The technique requires only measuring tapes, a computer, and two or three field personnel. Previous field experience is not required. The Interpoint method is a good choice for mapping trees where a high level of accuracy is desired, especially where expensive surveying equipment and trained personnel are not available."INTERPNT方法可仅基于树木直径与树间距离测量，生成高精度的树木空间分布图。有关该技术的更多细节，请参阅已发表的学术论文（Boose, E. R.、E. F. Boose 与 A. L. Lezberg，1998年，《一种利用距离测量绘制树木分布图的实用方法》，《生态学》(Ecology) 79卷：819-827页）。程序附带的文档中包含更多相关信息，下文转载了该论文的摘要："准确获取树木位置分布图对诸多生态学研究具有重要价值，但传统测绘方法常因树木遮挡视线而难以实施。本文提出一种受F. Rohlf与J. Archie早期研究启发的替代方案——点间法(Interpoint method)。该方法仅依赖树木直径与树间距离测量即可实现树木制图，由计算机完成必要的三角测量计算并检出粗差。我们曾在哈佛森林(Harvard Forest)的7块长期研究样地中应用点间法开展树木制图，样地面积介于0.25公顷（200株树木）至0.80公顷（889株树木）之间。为探究误差累积规律，我们设计了尽可能贴近野外实际场景的计算机模拟实验。模拟结果表明，该方法具备极高精度；若测量操作规范合理，误差累积速度极为缓慢——例如，在匹配野外测量误差的模拟场景中，1000株树木后的平均预测位置误差为9厘米，10000株树木后则为15厘米；对其中一块样地的独立测绘验证也得到了相近结果。该方法仅需卷尺、计算机与2至3名野外工作人员即可开展，无需具备专业野外测绘经验。对于需要高精度树木制图，且缺乏昂贵测绘设备与专业测绘人员的场景而言，点间法是极佳的选择。"