用OpenGL绘制物化探数据等值线  

Drawing the isopleths of geophysical and geochemical data with OpenGL

作　　者：叶娜[1] 许惠平[2] 赵彧[3] 覃如府[1] 

机构地区：[1]吉林大学地球探测与信息技术学院,吉林长春130026 [2]同济大学教育部海洋地质重点实验室,上海200092 [3]中国国家信息安全测评认证中心东北测评中心,吉林长春130061

出　　处：《世界地质》2004年第1期79-84,共6页World Geology

摘　　要：在Visual c++6.0环境下调用OpenGL库用网格法绘制标准物化探数据等值线,以图示形式给出数据集的二维和三维方式的等值线图,并给出相应的数字高程模型图,方便用户分析和理解数值分布情况。用线性内差法计算所有网格边上的等值点,横边上的等值点到前一个最近网格点的距离存放在二维数组X中,纵边上的等值点到下一个最近网格点的距离存放在二维数组Y中。调用自编的搜索函数在网格边上搜索等值线的线头,用追踪函数对这个线头所在线上的点进行追踪,并把追踪到的等值点的坐标按顺序存放在二维数组DW中,用OpenGL中绘制Bezier 曲线的方法分段连接DW数组中的等值点,并按颜色从红到蓝递变的顺序在屏幕上绘制等值线。In order to help users analyse and understand the distribution of data, the program draws isopleths of standard geophysical and geochemical data by Grid Method with the aid of Visual C++ 6.0 and OpenGL, shows two-dimensional and three-dimensional isopleths in form of the legend and Digital Elevation Model of corresponding dataset. The program can calculate all equal - value points on grids by the linear difference method, saving the distance from the horizontal equal-value points to the nearest grid points in the two-dimensional array X,the distance from the vertical equal-value points to the nearest grid points in the two - dimensional array Y. The program searches for the isopleths' beginning points on the grids through the search function written by the programmer. It traces all points that lie on these lines through the trail function and stores these points' coordinates in the two-dimensional array DW in order. The program links all equal-value points in the array DW and draws the isopleths on screen step by step by the principle of Bezier Curve in OpenGL. The lines' colors correspond to their values: red represents low value, blue represents high value.

关 键 词：网格法 等值线 OPENGL 

分 类 号：P631.84[天文地球—地质矿产勘探] TP391[天文地球—地质学]