Cost analysis of sand barriers in desertified regions based on the land grid division model

Sand barriers are the most widely used mechanical implements for wind-blown sand control and desertification prevention.However,there is no standard quantitative cost analysis of the sizes and materials required for sand barriers.In this study,based on the original land grid division model for optimal resource utilization,we calculated the total side lengths of square and regular hexagonal sand barriers with the sizes of 1.0 m×1.0 m,2.0 m×2.0 m,and 3.0 m×3.0 m in a desertified region of the Shapotou area on the southeastern edge of the Tengger Desert,China.Then,through literature review and social survey,we obtained the material cost and material utilization amount of sand barriers with different materials and sizes.Finally,we calculated the costs of square and regular hexagonal sand barriers comprised of wheat straw,corn stalk,Salix mongolica,poly lactic acid,magnesium cement,and high-density polyethylene,with the sizes of 1.0 m×1.0 m,2.0 m×2.0 m,and 3.0 m×3.0 m.The results show that the material cost of regular hexagonal corn stalk sand barriers with the size of 3.0 m×3.0 m is the lowest,while the material cost of square magnesium cement sand barriers with the size of 1.0 m×1.0 m is the highest.When using the same material,the cost of regular hexagonal sand barriers is lower than that of square sand barriers with the same size.When using the same size,the cost of sand barriers with corn stalk material is lower than that of sand barriers with other materials.Based on the above analysis,we can conclude that the economic benefits of regular hexagonal sand barriers are greater than those of square sand barriers.This study provides a theoretical basis for accurately calculating the material cost of sand barriers,particularly for the estimated cost of mechanized sand barrier engineering projects.

A spatial multi-scale integer coding method and its application to three-dimensional model organization

With the rapid development of digital earth,smart city,and digital twin technology,the demands of three-dimensional model data’s application is getting higher and higher.These data tend to be multi-objectification,multi-type,multi-scale,complex spatial relationship,and large amount,which brings great challenges to the efficient organization of them.This paper mainly studies the organization of three-dimensional model data,and the main contributions are as follows:1)A integer coding method of three dimensional multi-scale grid is proposed,which can reduce the four-dimensional(spatial dimension and scale dimension)space into one-dimensional,and has better space and scale clustering characteristics by comparing with various types of grid coding.2)The binary algebra calculation method is proposed to realize the basic spatial relationship calculation of three-dimensional grid,which has higher spatial relationship computing ability than 3D-Geohash method;3)The multi-scale integer coding method is applied to the data organization of three-dimensional city model,and the experiment results show that:it is more efficient and stable than the threedimensional R-tree index and Geohash coding method in the establishment of index and the query of three dimensional space.