C# GDAL显示TIF

/// <summary> 

/// GDAL栅格转换为位图 

/// </summary> 

/// <param name="ds">GDAL Dataset</param> 

/// <param name="showRect">显示区域</param> 

/// <param name="bandlist">需要显示的波段列表</param> 

/// <returns>返回Bitmap对象</returns> 

public Bitmap GetImage(OSGeo.GDAL.Dataset ds, Rectangle showRect, int[] bandlist) 

{ 

  int imgWidth = ds.RasterXSize;   //影像宽 

  int imgHeight = ds.RasterYSize;  //影像高 

 

  float ImgRatio = imgWidth / (float)imgHeight;  //影像宽高比 

 

  //获取显示控件大小 

  int BoxWidth = showRect.Width; 

  int BoxHeight = showRect.Height; 

 

  float BoxRatio = imgWidth / (float)imgHeight;  //显示控件宽高比 

               

  //计算实际显示区域大小，防止影像畸变显示 

  int BufferWidth, BufferHeight;    

  if (BoxRatio >= ImgRatio) 

  { 

                  BufferHeight = BoxHeight; 

                  BufferWidth = (int)(BoxHeight * ImgRatio); 

  } 

  else 

  { 

                  BufferWidth = BoxWidth; 

                  BufferHeight = (int)(BoxWidth/ImgRatio); 

  } 

 

  //构建位图 

  Bitmap bitmap = new Bitmap(BufferWidth, BufferHeight, 

                                                                                                   System.Drawing.Imaging.PixelFormat.Format24bppRgb); 

               

  if (bandlist.Length==3)     //RGB显示 

  { 

                  int[] r = new int[BufferWidth * BufferHeight]; 

                  Band band1 = ds.GetRasterBand(bandlist[0]); 

                  band1.ReadRaster(0, 0, imgWidth, imgHeight, r, BufferWidth ,BufferHeight, 0, 0);  //读取图像到内存 

 

                  //为了显示好看，进行最大最小值拉伸显示 

                  double[] maxandmin1 = { 0, 0 }; 

                  band1.ComputeRasterMinMax(maxandmin1,0); 

 

                  int[] g = new int[BufferWidth * BufferHeight]; 

                  Band band2 = ds.GetRasterBand(bandlist[1]); 

                  band2.ReadRaster(0, 0, imgWidth, imgHeight, g, BufferWidth, BufferHeight, 0, 0); 

 

                  double[] maxandmin2 = { 0, 0 }; 

                  band2.ComputeRasterMinMax(maxandmin2, 0); 

                               

                  int[] b = new int[BufferWidth * BufferHeight]; 

                  Band band3 = ds.GetRasterBand(bandlist[2]); 

                  band3.ReadRaster(0, 0, imgWidth, imgHeight, b, BufferWidth, BufferHeight, 0, 0); 

 

                  double[] maxandmin3 = { 0, 0 }; 

                  band3.ComputeRasterMinMax(maxandmin3, 0); 

 

                  int i, j; 

                  for (i = 0; i < BufferWidth; i++) 

                  { 

                                  for (j = 0; j < BufferHeight; j++) 

                                  { 

                                                  int rVal=Convert.ToInt32(r[i + j * BufferWidth]); 

                                                  rVal = (int)((rVal - maxandmin1[0]) / (maxandmin1[1] - maxandmin1[0]) * 255); 

 

                                                  int gVal=Convert.ToInt32(g[i + j * BufferWidth]); 

                                                  gVal = (int)((gVal - maxandmin2[0]) / (maxandmin2[1] - maxandmin2[0]) * 255); 

 

                                                  int bVal=Convert.ToInt32(b[i + j * BufferWidth]); 

                                                  bVal = (int)((bVal - maxandmin3[0]) / (maxandmin3[1] - maxandmin3[0]) * 255); 

 

                                                  Color newColor = Color.FromArgb(rVal, gVal, bVal); 

                                                  bitmap.SetPixel(i, j, newColor); 

                                  } 

                  } 

  }  

  else               //灰度显示 

  { 

                  int[] r = new int[BufferWidth * BufferHeight]; 

                  Band band1 = ds.GetRasterBand(bandlist[0]); 

                  band1.ReadRaster(0, 0, imgWidth, imgHeight, r, BufferWidth, BufferHeight, 0, 0); 

 

                  double[] maxandmin1 = { 0, 0 }; 

                  band1.ComputeRasterMinMax(maxandmin1, 0); 

                               

                  int i, j; 

                  for (i = 0; i < BufferWidth; i++) 

                  { 

                                  for (j = 0; j < BufferHeight; j++) 

                                  { 

                                                  int rVal = Convert.ToInt32(r[i + j * BufferWidth]); 

                                                  rVal = (int)((rVal - maxandmin1[0]) / (maxandmin1[1] - maxandmin1[0]) * 255); 

 

                                                  Color newColor = Color.FromArgb(rVal, rVal, rVal); 

                                                  bitmap.SetPixel(i, j, newColor); 

                                   } 

                   } 

   } 

 

   return bitmap; 

} 

 

主函数调用

private void ImageShow() 

    { 

        string filename=""; 

            OpenFileDialog dlg = new OpenFileDialog(); 

            dlg.Filter = "Tiff文件|*.tif|Erdas img文件|*.img|Bmp文件|*.bmp|jpeg文件|*.jpg|所有文件|*.*"; 

            if (dlg.ShowDialog() == DialogResult.OK) 

            { 

                filename = dlg.FileName; 

            } 

 

            if (filename == "") 

            { 

                MessageBox.Show("影像路径不能为空"); 

                return; 

            } 

        OSGeo.GDAL.Dataset ds= Gdal.Open(filename, Access.GA_ReadOnly); 

        if(ds==null) 

        { 

        MessageBox.Show("影像打开失败"); 

        return; 

        } 

        Rectangle pictureRect = new Rectangle(); 

            pictureRect.X = 0; 

            pictureRect.Y = 0; 

            pictureRect.Width = this.pictureBox1.Width; 

            pictureRect.Height = this.pictureBox1.Height; 

             

        int[] disband = {3,2,1}; 

              

        Bitmap bitmap = GetImage(ds, pictureRect, disband);   //遥感影像构建位图 

            pictureBox1.Image = bitmap;                   //将位图传递给PictureBox控件进行显示 

             

    }