从CAD中提取水深数据真实坐标算法研究

Research on echo sounding coordinate extraction algorithm from CAD

为了解决无法从CAD电子海图中,精确提取单物标水深(Single Object Depth)数据实测点位坐标的问题。以HYPACK海道测量软件生成的CAD水深图为样本,根据各种典型数字字符水深数据实例的归纳统计分析,发现了字符的宽度、高度、旋转角度、插入点坐标与实测坐标之间的数学关系,推导了根据CAD中水深字符插入点坐标反算水深实测坐标的公式。通过计算机编程,使用文件数据流I/O读写、多线程并发、数组分块等技术,直接访问CAD的DXF交换格式文件,实现了海量数据的快速读取、识别、分类、坐标推算和生成XYZ文件报表。将本文算法对各种典型和极端水深样例进行了检验,统计工程实例的反算水深坐标与原始实测坐标差值小于5 cm。

In order to solve the problem that Single Object Depth data cannot be accurately extracted from CAD electronic chart.Using the CAD bathymetric map samples generated by HYPACK hydrographic software,according to the induction and statistical analysis of various typical numerical character bathymetric data examples,the mathematical relationships between the width,height,rotation Angle,insertion point coordinates and measured coordinates of the characters were found,and the formula for calculating measured coordinates of the depth according to the insertion point coordinates of the bathymetric characters in CAD was derived.Through computer programming,using file data stream I/O reading and writing,multithreading concurrency,matrix block and other technologies,direct access to CAD DXF exchange format files,to achieve the rapid reading,identification,classification of massive data,coordinate calculation and the generation of XYZ file reports.Various typical and extreme water depth samples are tested by the proposed algorithm,and the difference between the inverse water depth coordinates and the original measured coordinates of the statistical engineering example is less than 5 cm.