private static void SaveBitmapDirect(string filename, Dataset ds, int xOff, int yOff, int width, int height, int imageWidth, int imageHeight)
{
if (ds.RasterCount == 0)
{
return;
}
int[] bandMap = new int[4] {
1, 1, 1, 1
};
int channelCount = 1;
bool hasAlpha = false;
bool isIndexed = false;
int channelSize = 8;
ColorTable ct = null;
// Evaluate the bands and find out a proper image transfer format
for (int i = 0; i < ds.RasterCount; i++)
{
Band band = ds.GetRasterBand(i + 1);
if (Gdal.GetDataTypeSize(band.DataType) > 8)
{
channelSize = 16;
}
switch (band.GetRasterColorInterpretation())
{
case ColorInterp.GCI_AlphaBand:
channelCount = 4;
hasAlpha = true;
bandMap[3] = i + 1;
break;
case ColorInterp.GCI_BlueBand:
if (channelCount < 3)
{
channelCount = 3;
}
bandMap[0] = i + 1;
break;
case ColorInterp.GCI_RedBand:
if (channelCount < 3)
{
channelCount = 3;
}
bandMap[2] = i + 1;
break;
case ColorInterp.GCI_GreenBand:
if (channelCount < 3)
{
channelCount = 3;
}
bandMap[1] = i + 1;
break;
case ColorInterp.GCI_PaletteIndex:
ct = band.GetRasterColorTable();
isIndexed = true;
bandMap[0] = i + 1;
break;
case ColorInterp.GCI_GrayIndex:
isIndexed = true;
bandMap[0] = i + 1;
break;
default:
// we create the bandmap using the dataset ordering by default
if (i < 4 && bandMap[i] == 0)
{
if (channelCount < i)
{
channelCount = i;
}
bandMap[i] = i + 1;
}
break;
}
}
// find out the pixel format based on the gathered information
PixelFormat pixelFormat;
DataType dataType;
int pixelSpace;
if (isIndexed)
{
pixelFormat = PixelFormat.Format8bppIndexed;
dataType = DataType.GDT_Byte;
pixelSpace = 1;
}
else
{
if (channelCount == 1)
{
if (channelSize > 8)
{
pixelFormat = PixelFormat.Format16bppGrayScale;
dataType = DataType.GDT_Int16;
pixelSpace = 2;
}
else
{
pixelFormat = PixelFormat.Format24bppRgb;
channelCount = 3;
dataType = DataType.GDT_Byte;
pixelSpace = 3;
}
}
else
{
if (hasAlpha)
{
if (channelSize > 8)
{
pixelFormat = PixelFormat.Format64bppArgb;
dataType = DataType.GDT_UInt16;
pixelSpace = 8;
}
else
{
pixelFormat = PixelFormat.Format32bppArgb;
dataType = DataType.GDT_Byte;
pixelSpace = 4;
}
channelCount = 4;
}
else
{
if (channelSize > 8)
{
pixelFormat = PixelFormat.Format48bppRgb;
dataType = DataType.GDT_UInt16;
pixelSpace = 6;
}
else
{
pixelFormat = PixelFormat.Format24bppRgb;
dataType = DataType.GDT_Byte;
pixelSpace = 3;
}
channelCount = 3;
}
}
}
// Create a Bitmap to store the GDAL image in
Bitmap bitmap = new Bitmap(imageWidth, imageHeight, pixelFormat);
if (isIndexed)
{
// setting up the color table
if (ct != null)
{
int iCol = ct.GetCount();
ColorPalette pal = bitmap.Palette;
for (int i = 0; i < iCol; i++)
{
ColorEntry ce = ct.GetColorEntry(i);
pal.Entries[i] = Color.FromArgb(ce.c4, ce.c1, ce.c2, ce.c3);
}
bitmap.Palette = pal;
}
else
{
// grayscale
ColorPalette pal = bitmap.Palette;
for (int i = 0; i < 256; i++)
{
pal.Entries[i] = Color.FromArgb(255, i, i, i);
}
bitmap.Palette = pal;
}
}
// Use GDAL raster reading methods to read the image data directly into the Bitmap
BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, imageWidth, imageHeight), ImageLockMode.ReadWrite, pixelFormat);
try
{
int stride = bitmapData.Stride;
System.IntPtr buf = bitmapData.Scan0;
using (RasterIOExtraArg arg = new RasterIOExtraArg())
{
GCHandle handle = GCHandle.Alloc("Test data", GCHandleType.Pinned);
try {
arg.nVersion = argVersion;
arg.eResampleAlg = resampleAlg;
arg.pfnProgress = new Gdal.GDALProgressFuncDelegate(ProgressFunc);
arg.pProgressData = handle.AddrOfPinnedObject(); // or System.IntPtr.Zero if not data to be added;
arg.bFloatingPointWindowValidity = 0;
ds.ReadRaster(xOff, yOff, width, height, buf, imageWidth, imageHeight, dataType,
channelCount, bandMap, pixelSpace, stride, 1, arg);
}
finally
{
handle.Free();
}
}
}
finally
{
bitmap.UnlockBits(bitmapData);
}
bitmap.Save(filename);
}
/// <summary>
/// Npp卫星数据读取
/// </summary>
/// <param name="bandData"></param>
/// <param name="dstBandIndex"></param>
/// <param name="xOffset"></param>
/// <param name="yOffset"></param>
/// <param name="blockWidth"></param>
/// <param name="blockHeight"></param>
/// <param name="srcImgSize"></param>
protected override void ReadImgBand(out ushort[] bandData, int dstBandIndex, int xOffset, int yOffset,
int blockWidth, int blockHeight, Size?srcImgSize = default(Size?))
{
//Npp的波段数据含有多种无效值，并且Radiance与Temperature数据集可能为Uint16也可能为Float
//65535 65534 65533 65532 65531 65530 65529 65528
//-999.9 -999.8 -999.7 -999.6 -999.5 -999.4 -999.3 -999.2
//如果需要判断读取的是反射率还是亮温，可以通过_prjSettings.IsRadRef||_prjSettings.IsRad
//_prjBands为待投影波段信息
//以下代码为假设对NPP数据进行亮温与反射率的读取
Band rasterBand = _rasterDataBands[dstBandIndex]; //
bandData = new ushort[blockWidth * blockHeight];
bool ok = false;
try
{
double ratioX = 1, ratioY = 1;
if (srcImgSize.HasValue)
{
ratioX = rasterBand.GetXSize() * 1.0 / srcImgSize.Value.Width;
ratioY = rasterBand.GetYSize() * 1.0 / srcImgSize.Value.Height;
}
Func <double, int> ToInt = t => Convert.ToInt32(t);
if (rasterBand.DataType == DataType.GDT_UInt16)
{
RasterIOExtraArg exArg = new RasterIOExtraArg()
{
eResampleAlg = RIOResampleAlg.GRIORA_NearestNeighbour,
dfXOff = xOffset * ratioX,
dfYOff = yOffset * ratioY,
dfXSize = blockWidth * ratioX,
dfYSize = blockHeight * ratioY,
nVersion = 1
};
ok = rasterBand.ReadRaster(ToInt(xOffset * ratioX), ToInt(yOffset * ratioY),
ToInt(blockWidth * ratioX), ToInt(blockHeight * ratioY),
bandData, blockWidth, blockHeight, 0, 0, exArg) == CPLErr.CE_None;
//无效值剔除
for (int i = 0; i < blockWidth * blockHeight; i++)
{
if (bandData[i] > 65527)
{
bandData[i] = 0;
}
}
}
else if (rasterBand.DataType == DataType.GDT_Float32)
{
RasterIOExtraArg exArg = new RasterIOExtraArg()
{
eResampleAlg = RIOResampleAlg.GRIORA_NearestNeighbour,
dfXOff = xOffset * ratioX,
dfYOff = yOffset * ratioY,
dfXSize = blockWidth * ratioX,
dfYSize = blockHeight * ratioY,
nVersion = 1
};
float[] tempBuf = new float[blockWidth * blockHeight];
ok = rasterBand.ReadRaster(ToInt(xOffset * ratioX), ToInt(yOffset * ratioY),
ToInt(blockWidth * ratioX), ToInt(blockHeight * ratioY),
tempBuf, blockWidth, blockHeight, 0, 0, exArg) == CPLErr.CE_None;
for (int i = 0; i < blockWidth * blockHeight; i++)
{
//过滤无效值为0
bandData[i] = tempBuf[i] < 0 ? (UInt16)0 : (UInt16)(tempBuf[i] * 10);
}
tempBuf = null;
}
if (!ok)
{
throw new Exception($"波段数据读取失败");
}
}
finally
{
if (!ok)
{
System.Diagnostics.Debug.WriteLine("ReadImgBand Index:{0}失败", dstBandIndex);
}
}
}
