public bool SetRegionToNoDataValue()
{
try
{
if (m_pSrcRaster == null || m_pClipPolygon == null || double.IsNaN(m_dbNoDataValue))
{
return(false);
}
IGeoDataset pSrcGeoDataset = m_pSrcRaster as IGeoDataset;
IExtractionOp pRasterExtractionOp = new RasterExtractionOpClass();
IRasterProps pSrcRasterProps = m_pSrcRaster as IRasterProps;
double dbCellSize = (pSrcRasterProps.MeanCellSize().X + pSrcRasterProps.MeanCellSize().Y) / 2;
//设置范围和分辨率
IRasterAnalysisEnvironment pRasterAnalysisEnv = pRasterExtractionOp as IRasterAnalysisEnvironment;
pRasterAnalysisEnv.SetCellSize(esriRasterEnvSettingEnum.esriRasterEnvValue, dbCellSize);
pRasterAnalysisEnv.SetExtent(esriRasterEnvSettingEnum.esriRasterEnvValue, m_pClipPolygon.Envelope, Type.Missing);
//pRasterAnalysisEnv.OutSpatialReference = (m_pSrcRaster as IRasterProps).SpatialReference;
//保留区域外的值，区域内的设置为原始栅格的无效值
IGeoDataset pDstGeoDataset = pRasterExtractionOp.Rectangle(pSrcGeoDataset, m_pClipPolygon.Envelope, true);
//逐点判断像素是否在区域内，在区域内则改变为设置值，否则不变
IRelationalOperator pRelationalOp = m_pClipPolygon as IRelationalOperator;
if (pDstGeoDataset is IRaster)
{
//得到原始栅格的对象，用于修改
IRaster2 pSrcRaster2 = m_pSrcRaster as IRaster2;
IRasterDataset2 pSrcRasterDataset2 = pSrcRaster2.RasterDataset as IRasterDataset2;
IRaster pTmpRaster = pSrcRasterDataset2.CreateFullRaster();
IRasterEdit pSrcEdit = pTmpRaster as IRasterEdit;
//得到图层NoDataValue
IRasterProps rasterProps = pSrcRaster2 as IRasterProps;
double noData = ClsGDBDataCommon.getNoDataValue(rasterProps.NoDataValue);
//得到输出的栅格
IRaster2 pDstRaster2 = pDstGeoDataset as IRaster2;
IRasterProps pDstRasterProps = pDstRaster2 as IRasterProps;
IRasterCursor pDstRasterCursor = pDstRaster2.CreateCursorEx(null);
//pDstRasterCursor.Reset();
do
{
//得到当前处理的块
IPixelBlock3 pixelBlock3 = pDstRasterCursor.PixelBlock as IPixelBlock3;
int nWidth = pixelBlock3.Width;
int nHeight = pixelBlock3.Height;
IPnt ptLeftTop = pDstRasterCursor.TopLeft;
//block值转数组时，NoData转换时有时为NoData，有时为栅格中的最小值
System.Array array = pixelBlock3.get_PixelData(0) as System.Array;
//逐点判断: 判断像素是否在区域内，在区域内则改变为设置值，否则不变
for (int i = 0; i < nWidth; i++)
{
for (int j = 0; j < nHeight; j++)
{
double dbX = double.NaN, dbY = double.NaN;
//得到当前像素点的地图坐标
int nCurrentX = Convert.ToInt32(ptLeftTop.X + i);
int nCurrentY = Convert.ToInt32(ptLeftTop.Y + j);
pDstRaster2.PixelToMap(nCurrentX, nCurrentY, out dbX, out dbY);
IPoint ptInMap = new PointClass();
ptInMap.X = dbX;
ptInMap.Y = dbY;
//判断是否在区域内
bool bFlag = pRelationalOp.Contains(ptInMap as IGeometry);
if (bFlag) //在当前区域内
{
object oValidValue = getValidType(pDstRasterProps, m_dbNoDataValue);
array.SetValue(oValidValue, i, j);
}
else
{
double v = Convert.ToDouble(array.GetValue(i, j));
if (v == 0 || v < -3.4e15 || v > 3.4e15)
//if (v == 0 || Math.Abs(v -noData) <1e18)
{
int col, row;
pSrcRaster2.MapToPixel(dbX, dbY, out col, out row);
//表示getpixelvalue为null表示nodata
object obj = pSrcRaster2.GetPixelValue(0, col, row);
if (obj == null)
{
object oValidValue = getValidType(pDstRasterProps, m_dbNoDataValue);
array.SetValue(oValidValue, i, j);
}
else
{
array.SetValue(obj, i, j);
}
}
}
}
}
pixelBlock3.set_PixelData(0, array);
//得到当前区域块在原图中的左上角像素坐标, 直接修改原栅格的数据
int nPixelLeftX = -1, nPixelLeftY = -1;
double dbMapLeftTopX = double.NaN, dbMapLeftTopY = double.NaN;
pDstRaster2.PixelToMap(Convert.ToInt32(ptLeftTop.X), Convert.ToInt32(ptLeftTop.Y), out dbMapLeftTopX, out dbMapLeftTopY); //得到当前块左上角的地理坐标
pSrcRaster2.MapToPixel(dbMapLeftTopX, dbMapLeftTopY, out nPixelLeftX, out nPixelLeftY);
IPnt ptPixelLeftTop = new PntClass();
ptPixelLeftTop.SetCoords(nPixelLeftX, nPixelLeftY);
if (pSrcEdit.CanEdit())
{
pSrcEdit.Write(ptPixelLeftTop, pixelBlock3 as IPixelBlock);
//pSrcEdit.Refresh();
}
else
{
return(false);
}
} while (pDstRasterCursor.Next() == true);
//更新
pSrcEdit.Refresh();
}
else
{
return(false);
}
return(true);
}
catch (System.Exception ex)
{
return(false);
}
}
