A Study On Algorithms And Applications For Accurate Calculation Of Forestland Surface Area

Forest resource investigation and monitoring is the eternal research theme of forest management.Forest is the basic condition for ensuring ecological security and providing ecological services,and forestland is the prerequisite and foundation for the existence and development of forest.The area change and type replacement of forestland will have a great impact on the evaluation of forest resource assets and ecosystem.Accurate and efficient measurement of forestland area is an important part of accurate forest monitoring and has important theoretical value and practical significance.Based on the analysis of the influencing factors of forestland area calculation and the conventional terrain surface area algorithms,two DEM-based forestland surface area algorithms are proposed in this paper.The first algorithm is the reproject integral algorithm,which realizes the accurate calculation of the forestland surface area by map projection reverse inference and area integral fitting.The second algorithm is the dynamic split algorithm.Based on the map projection reverse inference,the efficiency and accuracy of the algorithm are improved by optimizing the vector extraction of the overlay grid and the refinement of undulating terrain.The data of sample plots and RTK measured plot were used for experimental research and comparative analysis.The comparison results demonstrated that the reproject integral algorithm can obtain higher accuracy,but its operational efficiency is defective.While the dynamic split algorithm can ensure the accuracy of calculation and improve the efficiency.It is robust in large-scale data operation,and can effectively obtain the precise surface area of the forestland.Finally,the forestland surface area of Zhejiang Province was accurately calculated with the land cover data.The result showed that there was about 9.05% difference between the total forestland surface area and projected area in Zhejiang Province.This study realizes the accurate calculation of forestland surface area,and provides technical support for the efficient monitoring of forestland resources.This will assist the scientific decision-making of forest resource management,and provides data basis for the related research on forest carbon sink and ecosystem.