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“点抽样”以其高效率闻名于当代森林调查领域,而“双重点抽样”则可进一步减少工作量,且能保证精度要求,所以被广泛应用于生产实践.在处理外业数据时,如配合先进计算手段,则必然加倍提高工作效率和成果精度.本程序既可用于双重点抽样,也适用于点抽样;既适用于纯林,也可用于混交林.将外业绕测及控制检尺原始数据一次输入,随即可得总体每公顷蓄积量、生长量、标准误及抽样精度的估计值,以及确定两重样本单元数.如稍加修改还可用来求算每个林分的平均直径、每公顷株数、每公顷蓄积量和生长量,以适应森林经营、利用的需要.程序的编制以下列公式为依据:
“Spot sampling” is famous for its high efficiency in the field of contemporary forest surveys, and “double point sampling” can further reduce the workload, and can ensure the accuracy requirements, it is widely used in production practice.When processing field data, such as With the advanced calculation means, it is bound to double to improve work efficiency and accuracy of the results.This program can be used for both double sampling, but also for point sampling; both for pure forest, can also be used for mixed forest. Once the raw data is entered, an estimate of the total volume, growth, standard error, and sampling accuracy for each hectare is available as well as the number of units of double sample. A slight modification can also be used to calculate the average Diameter, number of plants per hectare, stock volume per hectare and growth volume to suit the needs of forest management and utilization.The preparation of the procedure is based on the following formula: