Thu thập dữ liệu đánh giá chính xác đòi hỏi phải hoàn thành ba bước bằng cách sử dụng cả các dữ liệu tham khảo và bản đồ được đánh giá: • Đầu tiên, việc đánh giá độ chính xác trang web mẫu phải được đặt trên các dữ liệu tham khảo và bản đồ. Điều này có thể là một nhiệm vụ tương đối đơn giản trong một khu vực đô thị, hoặc khó khăn hơn trong một wildland vài điểm mốc dễ nhận biết tồn tại. • Tiếp theo, các đơn vị mẫu phải được khoanh định. Đơn vị. | CHAPTER 4 Data Collection Accuracy assessment data collection requires completing three steps using both the reference data and the map being assessed First the accuracy assessment sample site must be located both on the reference data and on the map. This can be a relatively simple task in an urban area or far more difficult in a wildland where few recognizable landmarks exist. Next the sample unit must be delineated. Sample units must be exactly the same area on both the reference data and the map. Usually they are delineated once on either the reference data or map. Finally reference and map data must be collected for each sample unit to create reference and map labels based on the map classification scheme. The reference data may be collected from a variety of sources and may be captured either through observation or measurement. Serious oversights and problems can arise at each step of data collection. To adequately assess the accuracy of the remotely sensed classifications each step must be implemented correctly on every sample. If the reference data is inaccurate then the entire assessment becomes meaningless. Four basic considerations drive all reference data collection 1. What should be the source data for the reference samples Can existing maps or existing field data be used as reference data Should the information be collected from aerial sources or field visits 2. What type of information should be collected for each sample Should measurements be taken or are observations adequate 3. When should the reference data be collected During initial field investigations when the map is being made or only after the map is completed What are the implications of using old data for accuracy assessment 4. How do we insure that the reference data is collected correctly objectively and consistently There are many methods for collecting reference data some of which depend on making observations qualitative assessments and some which require detailed 1999 by CRC Press .
