In the black soil region of Northeast China, gully erosion is severe and widespread. Currently, gully monitoring in this area relies predominantly on manual interpretation, highlighting the urgent need for a rapid extraction method. This study selects the Mashezi River Basin in Binxian country, Heilongjiang province, a region heavily affected by gully erosion, as study area. Utilizing GF-7 satellite imagery and comparing with manual interpretation results, the accuracy of three automatic gully extraction methods is evaluated:flow-directional detection, machine learning and deep learning. The findings are as follows:① The flow-directional detection method depends on high-precision topographic data. The vertical accuracy of topographic data generated from GF-7 stereo images is poor, resulting in an overall extraction accuracy of only 6. 7%, and this method is unable to automatically extract permanent gullies and ephemeral gullies from GF-7. ②The machine learning approach requires manual setting of segmentation parameters and design of classification features, limiting its degree of automation. It achieves an overall extraction accuracy of 50. 7%, with a precision of 83. 1% for permanent gullies and only 9. 2% for ephemeral gullies. ③The deep learning method adopts an end-to-end approach, without the need to design feature extractors. It offers a high degree of automation with an overall extraction accuracy of 60. 8%, achieving 68. 1% accuracy in identifying permanent gullies and 69. 7% in recognizing ephemeral gullies.
black soil region in Northeast ChinaGF-7 satellite imageflow-directional detectionmachine learningdeep learning