基于海量多波束数据的海底DEM简化精度分析

Precision analysis of submarine DEM simplification based on large number of multibeam data

海底数字高程模型(digital elevation model,DEM)是海洋地理信息系统分析和应用的基础。本文研究了基于规则格网和不规则三角形网(TIN)的DEM简化,并对简化后的模型进行了精度分析。利用数据分块结构对水深数据进行快速检索,采用不同的格网尺度实现了格网DEM的简化。基于数据点的重要性,采用点删除的策略进行TIN简化。实验证明:两种简化模型的精度都与水深数据点的密度和海底地形的复杂程度有关;当数据密度较高时,TIN简化模型精度优于格网简化模型,当数据密度较低时,格网简化模型精度优于TIN简化模型;对于本文选用的多波束水深数据,当两种简化模型的简化率达到20%时,两种简化模型的精度大致相等。

Submarine digital elevation model(DEM) is a foundation of analysis and application for submarine geographic information system.Methods for simplifying DEM based on grid and triangulated irregular network(TIN) were studied and precisions of simplified models were analyzed in the paper.Depths were rapidly searched by utilizing block structure,and then the DEM based on regular grid was simplified with different grid scales.The DEM based on TIN was simplified by deleting unimportant points.Experimental results demonstrated as follows: precisions of simplified models depend on the data density and submarine terrain;simplified model based on TIN is more accurate than that of the simplified model based on regular grid in sea areas with high-density depth;the precision of the simplified model based on regular grid is higher than that of the simplified model based on TIN when density of depth data is low;precisions of both simplified models are approximately equal when simplified ratio is 20 percent for selected multibeam data in this paper.