小区植被覆盖度动态快速测量方法研究

Monitoring of Plant Coverage of Plots by Visual Estimation and Overhead Photograph

选择北京密云、怀柔的 2块农地作为样地 ,对照相法测量植被覆盖度的效果进行了分析 ,并将之与目估法进行了对比。结果显示照相结合数字图像处理计算植被覆盖度的方法便捷客观 ,计算植被覆盖度的最大绝对误差不到 5 %,而目估法测量植被覆盖度具有明显的不可靠性 ,不同人的目估结果有明显差异。图像分类计算覆盖度的最大误差只相当于个人目估最大绝对误差的 10 .9%,相当于 7人目估平均最大绝对误差的 43.1%。

Plant coverage is a very important ecological index and it is essential for predicting soil loss quantitatively. The plant coverage of two fields located in Beijing city was measured periodically in order to analyze the errors of overhead photograph and visual estimation for plant coverage. The results showed that the overhead photograph combined image processing was an accurate and fast method, and the maximal absolute error was less than 5%. The plant coverage estimated by different persons have significant difference. The individual maximal absolute error was up to 40% and average maximal absolute error for 7 persons was up to 10.2%.