Fig. 1. Overview of the study area

Fig. 2. The flowchart of this study

Fig. 3. Distribution of field crop row direction

Fig. 4. Results of pretreatment

Fig. 5. Example of the shape of the land plots

Fig. 6. Results of minimum area rectangle fitting and long edge recognition for irregular land plots

Fig. 7. Accuracy of different threshold intervals and different thresholds

Fig. 8. Results for probabilistic Hough transform algorithms （top four） and LSD algorithms （bottom four） in different threshold intervals

Fig. 9. Results for probabilistic Hough transform algorithms （top four） and LSD algorithms （bottom four） with different thresholds

Fig. 10. Schematic diagram of the fracture phenomenon in the binary image of the land parcel

Fig. 11. Automatic extraction of land plots boundary results based on cloud platform