使用GDAL查询tiff影像任意一点的高程

{ //开始调用GDAL int i, xSize, ySize, bandNum; GDALDataset *poDataset; //注册 GDALAllRegister(); //坐标转换参数 double geoInfo[6]; //打开文件获取数据集 poDataset = (GDALDataset *)GDALOpen("G:\\dem\\***.tif", GA_ReadOnly); //存储影像值 int *pafScan; if (poDataset != NULL) { poDataset->GetRasterBand(1)->GetNoDataValue(&i); //获取图像的长宽像素值 xSize = poDataset->GetRasterXSize(); ySize = poDataset->GetRasterYSize(); //获取影像转换参数 poDataset->GetGeoTransform(geoInfo); // geoInfo[0] /* top left x， 图像左上角x坐标值*/ // geoInfo[1] /* w-e pixel resolution，图像横坐标 ？米/每像素 */ // geoInfo[2] /* rotation, 0 if image is "north up" */ // geoInfo[3] /* top left y 图像左上角y坐标值*/ // geoInfo[4] /* rotation, 0 if image is "north up" */ // geoInfo[5] /* n-s pixel resolution 图像纵坐标 ？米/每像素*/ //获取影像波段数 bandNum = poDataset->GetRasterCount(); pafScan = new int[xSize * ySize ]; //指向存储数据,一个波段 //将影像第一个波段的全部值存入pafscan poDataset->GetRasterBand(1)->RasterIO( GF_Read, 0, 0, xSize, ySize, pafScan, xSize, ySize, GDT_Float32, 0, 0);//将一个波段存入pafScan } else { exit(1); } //左上角坐标值 double x0, y0; x0 = geoInfo[0]; y0 = geoInfo[3]; //经纬度转化为栅格点 double dx, dy; dx = 114.355727 - x0; dy = 30.528824 - y0; int x = (int)(dx / geoInfo[1]); int y = (int)(dy / geoInfo[5]); int band=1;//波段 float buffer[1];//申请一个尽可能小的缓存区 float height= 0; //通过经纬度查询当前高度值 if poDataset->GetRasterBand(1)->RasterIO( GF_Read, // GDALRWFlag eRWFlag,----> eRWFlag Either GF_Read to read a region of data, or GF_Write to write a region of data. x, // int nXOff, ----> The pixel offset to the top left corner of the region of the band to be accessed. This would be zero to start from the left side. y, // int nYOff, ----> The line offset to the top left corner of the region of the band to be accessed. This would be zero to start from the top. 1, // int nXSize, ----> The width of the region of the band to be accessed in pixels. 1, // int nYSize, ----> The height of the region of the band to be accessed in lines. (void *)buffer,// void * pData, ----> The buffer into which the data should be read, or from which it should be written. This buffer must contain at least nBufXSize * nBufYSize * nBandCount words of type eBufType. It is organized in left to right,top to bottom pixel order. Spacing is controlled by the nPixelSpace, and nLineSpace parameters. 1, // int nBufXSize, ----> the width of the buffer image into which the desired region is to be read, or from which it is to be written. 1, // int nBufYSize, ----> the height of the buffer image into which the desired region is to be read, or from which it is to be written. GDT_Float32, // GDALDataType eBufType, ----> the type of the pixel values in the pData data buffer. The pixel values will automatically be translated to/from the GDALRasterBand data type as needed. 1, // int nBandCount, ----> the number of bands being read or written. &band, // int * panBandMap, ----> the list of nBandCount band numbers being read/written. Note band numbers are 1 based. This may be NULL to select the first nBandCount bands. 0, // int nPixelSpace, ----> the byte offset from the start of one pixel value in pData to the start of the next pixel value within a scanline. If defaulted (0) the size of the datatype eBufType is used. 0, // int nLineSpace, ----> The byte offset from the start of one scanline in pData to the start of the next. If defaulted (0) the size of the datatype eBufType * nBufXSize is used. 0 //int nBandSpace , ----> the byte offset from the start of one bands data to the start of the next. If defaulted (0) the value will be nLineSpace * nBufYSize implying band sequential organization of the data buffer. ) == CE_Failure) cout << "poDataset->RasterIO failure" << endl; else { height=buffer[0]; } //最后一定要关闭影像 GDALClose(poDataset); }