基于几何学特征的1∶50000水系沉积物自动化布点方法

    A geometry-based method for automated sampling point arrangement in 1∶50,000 stream sediment surveys

    • 摘要: 目前,在地球化学水系沉积物勘查工作中,采样点布设常常依赖人工进行,但人工布设存在工作量大、主观随意性强、流域控制不充分等问题,且布设后缺乏有效的质量检查,致使布设完成后的合理性难以得到保障,影响野外工作的实施和整个化探解释结果的可靠性。为了解决以上问题,本研究通过ArcGIS,基于水系的几何构型特点(水系级别及长度)进行计算机自动化科学布点,并构建设计点合理性检验模型评估自动布点的分布合理性和可采合理性。将该方法运用于1∶50 000三河坝幅的马家沟区域水系沉积物样点布设工作中,自动化布点的结果最近邻比率指数为1.1,分布均匀,无不合理空白区,其中1级水系上布点占比84.7%,布点密度4.6点/km2,布设符合规范要求且具备野外作业的条件。该方法有效提高了室内布设的工作效率和点位的合理性,具有很高的实际应用价值。

       

      Abstract: In current geochemical surveys of stream sediments, manual sampling point arrangement predominates. However, manual arrangement faces several challenges, including heavy workload, high subjectivity, and insufficient control over river basin coverage. Moreover, the lack of effective quality inspection after sampling point arrangement renders it difficult to ensure the rationality of the arrangement. These issues affect field operations and the reliability of subsequent geochemical interpretations. Using the ArcGIS system, this study implemented computer automation-based scientific sampling point arrangement as per the geometric characteristics (e.g., order and length) of streams. Furthermore, a model for the verification of sampling point rationality was developed to assess the rationality of the distribution and sampleability of the automatically arranged sampling points. The proposed method was applied to the sampling point arrangement of stream sediments in the Majiagou area within the 1∶50,000 Sanheba map sheet. The results indicate that the automated arrangement achieved a nearest neighbor index of 1.1. This finding suggests a uniform sampling point distribution, with an absence of unreasonable gaps. Notably, 84.7% of the sampling points were distributed along the first-order streams, with a sampling density of 4.6 points/km2. The resulting sampling point layout complies with the requirements in relevant specifications and satisfies the prerequisites for field operations. Therefore, the method of automated sampling point arrangement significantly enhances the efficiency and reasonableness of indoor sampling point arrangement, holding high practical value.

       

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