Chương này trình bày các kỹ thuật phân tích cơ bản cần thiết để thực hiện một đánh giá chính xác. Chương này bắt đầu bằng việc thảo luận đầu trang web đánh giá cụ thể không. Tiếp theo, các kỹ thuật đánh giá trang web cụ thể sử dụng các ma trận lỗi được trình bày theo sau bởi tất cả các công cụ phân tích được tiến hành từ nó bao gồm các khoảng tin cậy tính toán, kiểm tra sự khác biệt đáng kể, và điều chỉnh ước tính khu vực. Một ví dụ số được trình. | CHAPTER 5 Basic Analysis Techniques This chapter presents the basic analysis techniques needed to perform an accuracy assessment. The chapter begins by discussing early non-site specific assessments. Next site specific assessment techniques employing the error matrix are presented followed by all the analytical tools that proceed from it including computing confidence intervals testing for significant differences and correcting area estimates. A numerical example is presented through the entire chapter to aid in understanding of the concepts. NON-SITE SPECIFIC ASSESSMENTS In a non-site specific accuracy assessment only total areas for each category mapped are computed without regard to the location of these areas. In other words a comparison between the number of acres or hectares of each category on the map generated from remotely sensed data and the reference data is performed. In this way the errors of omission and commission tend to compensate for each other and the totals compare favorably. However nothing is known about any specific location on the map or how it agrees or disagrees with the reference data. A simple example quickly demonstrates the shortcomings of the non-site specific approach. Figure 5-1 shows the distribution of the forest category on both a reference image and two different classifications generated from remotely sensed data. Classification 1 was generated using one type of classification algorithm . supervised unsupervised or nonparametric etc. while classification 2 employed a different algorithm. In this example only the forest category is being compared. The reference data shows a total of 2 435 acres of forest while classification 1 shows 2 322 acres and classification 2 shows 2 635 acres. In a non-site specific assessment you would conclude that classification 1 is better for the forest category because the total number of forest acres for classification 1 more closely agrees with the number of acres of forest on the reference .
