Scale evaluation method for fragmented terrain vector data
To address the issues of low efficiency and low reliability in manually determining the scale of terrain vector data,a terrain vector data scale evaluation method based on natural laws is proposed to achieve automation in terrain vector data scale determination in this paper.Based on the characteristics that the node density of terrain vector data at different scales changes with the scale,this method uses the principles of natural law and statistical knowledge to determine the theoretical values of node density intervals at different scales and different elements.For the terrain vector data to be identified,compare its node density with the node density interval of the known scale vector data.If it falls within the node density interval of the scale,it is inferred as the scale data,and then automatic scale determination is achieved.Finally,the feasibility of the evaluation meth-od was verified using two elements:contour lines and water systems.The experimental results show that the accuracy of auto-matic scale determination of 1:1 000 000,1:250 000 and 1:50 000 terrain vector data based on the algorithm proposed in this paper reaches 93.97％,94.04％and 92.47％,respectively,and the overall accuracy of scale determination of vector data reaches 93.21％,greatly improving the accuracy and efficiency of scale judgment,and providing technical support for geo-graphic information security assurance.
vector datanatural principlenode density indexscale evaluation
NETL
NSTL
万方数据
