[geos]Geometry基本的几何对象

读取shp中的点，读取shp中的线，

（1）读取shp中的多边形，修改属性字段的值。

类库版本：geos3.6.2，shapelib1.3

添加引用：

#include "geos.h"
using namespace geos;

定义类变量：

 GeometryFactory::unique_ptr global_factory;

构造中初始化

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// Define a precision model using 0,0 as the reference origin // and 2.0 as coordinates scale. PrecisionModel *pm = new PrecisionModel(1.0, 0, 0);   // Initialize global factory with defined PrecisionModel // and a SRID of -1 (undefined). global_factory = GeometryFactory::create(pm, -1);

 

方法体中调用：　　

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std::string::size_type pos=pszShapeFile.find('.'); /*std::string ext=filename.substr(pos==string::npos? pszShapeFile.length():pos+1); */   std::string tmp=pszShapeFile; std::string dbfname=tmp.replace(tmp.begin()+pos+1,tmp.end(),"dbf"); SHPHandle hShp= SHPOpen(pszShapeFile.c_str(), "r"); DBFHandle   hDBF = DBFOpen( dbfname.c_str(), "r+b" ); if( hDBF == NULL ) {     return; } int idxCeiling=DBFGetFieldIndex(hDBF,"CeilingZ"); int idxFloor=DBFGetFieldIndex(hDBF,"FloorZ"); if (idxCeiling==-1) {     idxCeiling=DBFAddField(hDBF,"CeilingZ",FTDouble, 10, 4); } if (idxFloor==-1) {     idxFloor=DBFAddField(hDBF,"FloorZ",FTDouble, 10, 4); } int nShapeType, nVertices; int nEntities = 0; double* minB = new double[4]; double* maxB = new double[4]; SHPGetInfo(hShp, &nEntities, &nShapeType, minB, maxB); printf("ShapeType:%d\n", nShapeType); printf("Number of Rooms: %d\n", nEntities); if (nShapeType==SHPT_POLYGON ||nShapeType==SHPT_POLYGONZ) {     geos::geom::CoordinateArraySequenceFactory csf;       for (int idx = 0; idx < nEntities;idx++)     {         std::pair<int, int> pair;         cell_residual.resize (num_of_hists, pair);         int iShape = idx;         SHPObject *obj = SHPReadObject(hShp, iShape);           int parts = obj->nParts;         int verts=obj->nVertices;         printf("nParts:%d\n", parts);         printf("nVertices:%d\n", verts);         geos::geom::CoordinateSequence* cs1 = csf.create(verts,2);         for (size_t j = 0; j < verts; j++)         {             double x = obj->padfX[j];             double y = obj->padfY[j];             cs1->setAt(Coordinate (x,y,0),j);         }         geos::geom::LinearRing* ring1 = global_factory->createLinearRing(cs1);         geos::geom::Geometry* p1 = global_factory->createPolygon(ring1,NULL);         //根据房间范围遍历每一个点         for (int i=0;i<pcl_t_cloud->points.size();i++)         {             pcl::PointXYZ pt=pcl_t_cloud->points[i];               geos::geom::Coordinate coord(pt.x,pt.y,0);             geos::geom::Geometry* pt_g=global_factory->createPoint(coord);             bool flag=p1->contains(pt_g);             if (flag)             {                 int indx=floor((pt.z-minPt.z)/interval);                 if (indx<num_of_hists)                 {                     cell_residual[indx].first = indx;                     int ptscount=cell_residual[indx].second;                     cell_residual[indx].second = ptscount+1;                 }             }         }         //排序高度数组         std::sort (cell_residual.begin (), cell_residual.end (), comparePair2);         //得到最大和最小值,统计数目最多的两个         double minZ=cell_residual[num_of_hists-2].first*interval + minPt.z;         double maxZ=cell_residual[num_of_hists-1].first*interval + minPt.z;         //赋值2个属性         DBFWriteDoubleAttribute(hDBF, iShape ,idxCeiling,std::min(minZ,maxZ) );         DBFWriteDoubleAttribute(hDBF, iShape ,idxFloor,std::max(minZ,maxZ) );         cell_residual.clear();     }       } DBFClose( hDBF ); SHPClose(hShp);