由不规则离散点集生成TIN与GRID DEM.doc

由不规则离散点集生成TIN与GRID DEM ????现阶段生成数字高程模型（DEM）的方法较多，如以摄影测量得到的像对为数据源跟踪生成等高线及DEM，由机载激光测距仪记录规则点集后生产数据，也可采用传统的地形图扫描后跟踪等高线，记录一连串离散点集，接着运用各类算法进行处理，最后生成不规则三角网（TIN）与规则格网（GRID）DEM的方法。本文主要介绍的就是以等高线（参考图一）和离散点集为数据源，产生TIN与GRID DEM的技术路线。具体步骤如下： 1） 2）XY轴方向上最小最大数值，压缩数据范围，避免数据范围跨度太大或太小，即出现数据分布稠密或稀疏的情况。 ??? while (!_demfile.eof())?????????????????????????????????????????????????????????????? { ????????? _demfile point3dXYZ[i][0] point3dXYZ[i][1] point3dXYZ[i][2]; ???????? ???????? point3dXYZ[i][2] = point3dXYZ[i][2] / 2;?? //因为XY轴在随后调整，因此相应调Z轴数值 ???????? ?if(xMinpoint3dXYZ[i][0]) xMin = point3dXYZ[i][0];//得到整个范围的最大与最小数值 ???????? ?if(xMaxpoint3dXYZ[i][0]) xMax = point3dXYZ[i][0]; ???????? ?if(yMinpoint3dXYZ[i][1]) yMin = point3dXYZ[i][1]; 牋牋牋牋 爄f(yMaxpoint3dXYZ[i][1]) yMax = point3dXYZ[i][1];][1]; 牋牋牋牋 爄f(zMinpoint3dXYZ[i][2]) zMin = point3dXYZ[i][2];][1]; 牋牋牋牋 爄f(zMaxpoint3dXYZ[i][2]) zMax = point3dXYZ[i][2];][1]; 牋牋牋牋 爄++;Maxp 牋?}牋 牋?_demfile.close();牋牋牋牋牋牋牋牋牋牋?//Max = point3d文件流读取完毕，关闭 _demfile.clear();????????????????????? //文件流清除 3）TIN中点，线，三角形和网的定义。 class AFX_EXT_CLASS TIN_Point??????????????????????????????????????????????????? {???????????????????????? //TIN中的点 ??? friend class TIN; public: int????? Get_ID?? (void)?? {?? return( m_ID );}???? //ID数值 ??? const POINT3d ????? Get_Point??? (void){?return( m_Point );?? }??????? //普通的点 ??? double?????????????? Get_X(void)?{return( m_Point[0] );??? }??????? //点上的X数值 ??? double?????????????? Get_Y(void)?{return( m_Point[1] );??? }??????? //点上的Y数值 ??? double?????????????? Get_Z(void)?{return( m_Point[2] );??? } ??? int????? Get_Neighbor_Count?? (void){?return( m_nNeighbors );?? }??????? //邻接点的个数 ??? TIN_Point *Get_Neighbor?????????? (int iNeighbor)?{?return( iNeighbor = 0 iNeighbor m_nNeighbors ? m_Neighbors[iNeighbor] : NULL );?}?? //得到某一邻接点 ??? int????? Get_Triangle_Count?? (void){return( m_nTriangles );}?? //得到邻接三角形个数 ??? TIN_Triangle *?? Get_Triangle(int iTriangle)?? {?? return( iTriangle = 0 iTriangle m_nTriangles