河川區域的監測是台灣水資源管理中一個重要的工作，然而河川區域內的使用行為日趨複雜，倘若以河川局之有限之人力與資源，欲達到有時效性之監控與即時嚇阻河川區域內違法之行為，有其實際困難之處，故以先進而成熟的科學技術對河川流域進行長期的監測更顯為重要。有鑑於此，本計畫利用高解析遙測資源衛星，以遙測衛星高時效與大範圍監測的特性，針對河川區域內進行常態性的變遷偵測。本計畫的監測範圍包含中央管河川(含淡水河水系及磺溪水系)等26條河川，監測頻率為每兩週一期；工作內容主要為每期進行河川區域的變遷偵測，透過網路通報的方式將變遷點的資訊即時傳遞至查報單位，經查報單位於現地調查後，再利用網路回報的方式將查報的結果上傳至網站。由於本計畫是常態性大區域之變遷偵測，因此第一階段的變遷點偵測是以電腦進行判釋，但考量到河川巡防人員之實際工作情況，再以人為判釋的方式進行變異點之過濾，如此可減少巡防人員之工作量。目前電腦判釋是利用變異向量分析法(Change Vector Analysis, CVA)與常態化差異植生指數(Normalized Difference Vegetation Index, NDVI)進行河砂開採及河川土地變異之監測；人為判釋則以實際變遷影像的光譜變化與紋理特徵，配合航空照片、向量地圖與土地利用圖等輔助圖資進行可疑變異點之篩選。本計畫執行期間由98年6月25日至98年12月25日，將進行12期的變遷偵測與通報(監測頻率為每兩週一次)。監測影像來源以福衛二號為主，SPOT5衛星為輔，以彌補因為氣候所造成之福衛二號影像的不足。並基於資料共享、資源共用的角度，將於計畫執行期間便將變異區位相關的通報與查報等重要資料項目，與本署「河川管理整合性資訊化系統」等相關系統之資訊交換整合。希望能夠有效的協助巡防人員進行河川區域變遷點查報，並提高河川巡防取締違法作為之成效。The monitoring of river area is an important task for water resource management. However, the land use in river area is getting complicated and the illegal use of river area is also getting serious, it is almost impossible to detect the illegal activity in whole river area by only the limited human resource. The purpose of this project is to use remote sensing images to regularly detect the change spots in river area. Moreover, the change information will be delivered to the local patrol units via internet for the field investigation in the period of two weeks. The investigation results and the field photos will then be uploaded and integrated to the wet-based database management system. Firstly, the change detection using remote sensing images is implemented in an automatic procedure. Then the manual inspection procedure will be involved to select the change spots with highly questionable condition. The project is carried out from 25 June 2009 to 25 December 2009. Since the monitoring is implemented on the basis of two weeks, there will be totally 12 change spot notifications and investigation during the project period. In the project, the major image sources will be obtained from FORMOSAT-2 with the occasional use of SPOT images. Therefore, the volumes of the images not only provide the total coverage over the study areas, but also keep the project management in schedule. Based on the point of view of sharing the information, the results of change detection will be integrated into the “River Management and Integration Information System”. The purpose of this project is to assist the river patrolmen in monitoring and managing the land of river bank in an efficient way. 研究期間：9806 ~ 9812
