Data overview: Zhangye's canals are divided into five levels: trunk, branch, Dou, Nong and Mao. Generally, the agricultural canals are not lined, and the maoqu is a field project. Therefore, the three levels of trunk, branch and Dou and a small part of the agricultural canals are mainly collected. The irrigation canal system data includes two main canals (involving multiple irrigation districts), 157 main canals (within a single irrigation district), 782 branch canals, 5315 doucanals, with a total length of 8, 745.0km.

Data acquisition process: the irrigation canal system data acquisition adopts the method of combining remote sensing interpretation and GPS field measurement. GPS direct acquisition channel is the most effective method, but the workload of GPS acquisition channel is too large, we only verify the survey in some irrigation areas. The main way is to first collect the irrigation area schematic maps drawn manually by each water pipe, most of which are not located, only the individual irrigation areas such as Daman and shangsan are located based on the topographic map, and some irrigation areas in Gaotai County use GPS to locate some channels. Referring to the irrigation area schematic diagram, the channel spatial positioning is based on quikbird, aster, TM remote sensing image and 1:50000 topographic map. For the main and branch canals, because of the obvious linear characteristics on the remote sensing image and the general signs on the topographic map, it can be more accurate positioning. For the douqu, the area with high-resolution image can be located more accurately, while the other areas can only be roughly located according to the fuzzy linear characteristics of the image and the prompt information of the irrigation area staff, with low positioning accuracy. At the same time, each water pipe station provides channel attribute data, which corresponds to the spatial data one by one. After the first draft of the channel distribution map is completed, it is submitted to the personnel familiar with the channel distribution of each water pipe for correction twice, the first time is mainly to remove the weight and make up the leakage, the second time is mainly to correct the location and improve the attribute data.

Data content description: the fields in the attribute table include code, name of district and county, name of irrigation area, channel whole process, channel name, channel type, location, total length, lined, design flow, design farmland, design forest and grass, actual irrigation farmland, actual irrigation forest and grass, water right area and remarks. Code example: g06g02z15d01, in which the first letter represents the county name, the second and third numbers represent a county (District) number, the fourth to sixth characters represent the main channel code, the seventh to ninth characters represent the branch channel code, and the tenth to twelfth characters represent the douqu code.