Abstract:
Background The existing county-scale soil erosion evaluation method mostly uses raster structure as the basic calculation unit, leading to multiple raster numbers and multiple erosion intensities in a single vector plot, which makes it difficult to directly apply to vector plot-based soil erosion control and planning. Therefore, studying the impact of different spatial data structures of raster and vector on soil erosion calculation and evaluation is of great significance to the dynamic monitoring of soil erosion and the application of results, and to serve soil and water conservation planning and soil erosion control.
Methods This study used Ruzhou city, Henan province as the research area, based on two different spatial data structures of raster and vector, combined with China's soil loss equation and remote sensing monitoring, the differences in soil erosion among 5 methods were compared and analyzed.
Results 1) The raster statistics method based on raster calculation took 8 min, which quickly and accurately calculated the soil erosion area and intensity, and accurately described the erosion area and intensity of different land uses, but the mapping effect of aggregation index was bad. This method was suitable for soil erosion evaluation at county scale that did not require mapping. 2)The software judgment method presented the smallest difference in calculation results, and demonstrated the best effect in drawing. Compared with the raster statistics method, the software judgment method had a difference of 0.05 km2 in the erosion area, with a difference rate of 0.01%, and it had a small difference in the erosion area of different erosion intensity and different land use, which took 13 min. The aggregation index was 96.81%, which was good mapping effect. It is suitable for soil erosion evaluation and mapping at county level. 3)The calculation time of the land parcel evaluation method was moderate, which was 16 min. But the erosion area difference was 64.63 km2, the difference rate was 16.02% and the area of different erosion intensity cannot be provided. It was not suitable for soil erosion evaluation at the county scale. 4) There were large differences in soil erosion area, intensity and erosion area of different land use between two vector calculation methods. The large amount of vector data led to longer calculation time, but the advantage was that the mapping effect was better. These two methods were suitable for calculation and evaluation of soil erosion in plain areas with relatively consistent soil types, terrain slopes, and vegetation coverage.
Conclusions The research results may provide reference for water erosion evaluation, dynamic monitoring of soil and water loss and application of the results at county level.