public System.Windows.Point ImageToWorld(double x, double y)
{
double[] adfGeoTransform = new double[6];
double[] p = new double[3];
dataset.GetGeoTransform(adfGeoTransform);
p[0] = adfGeoTransform[0] + adfGeoTransform[1] * x + adfGeoTransform[2] * y;
p[1] = adfGeoTransform[3] + adfGeoTransform[4] * x + adfGeoTransform[5] * y;
SpatialReference src = new SpatialReference("");
string s = dataset.GetProjectionRef();
src.ImportFromWkt(ref s);
SpatialReference wgs84 = new SpatialReference("");
wgs84.SetWellKnownGeogCS("WGS84");
CoordinateTransformation ct = new CoordinateTransformation(src, wgs84);
ct.TransformPoint(p);
ct.Dispose();
wgs84.Dispose();
src.Dispose();
return(new System.Windows.Point(p[0], p[1]));
}
// 将给定Tif转换为Web Mercator投影
public void TransformTiff(Dataset ds, double[] VerticeX, double[] VerticeY, string FilePath, ResampleAlg eResampleMethod)
{
//获取Web墨卡托坐标系
SpatialReference Mercator = new SpatialReference("");
Mercator.ImportFromEPSG(3857); // Web Mercator
Mercator.SetMercator(0d, 0d, 1d, 0d, 0d);
string MercatorWkt;
Mercator.ExportToWkt(out MercatorWkt);
//原栅格坐标信息
SpatialReference Raster_spf = new SpatialReference(ds.GetProjectionRef());
//影像四个顶点投影转换
CoordinateTransformation coordinateTrans = Osr.CreateCoordinateTransformation(Raster_spf, Mercator);
coordinateTrans.TransformPoints(4, VerticeX, VerticeY, null); //VerticeX和VerticeY存储的是影像四个顶点坐标
coordinateTrans.Dispose();
//计算重投影后栅格顶点坐标
double dbMinx = 0;
double dbMaxx = 0;
double dbMiny = 0;
double dbMaxy = 0;
dbMinx = Math.Min(Math.Min(Math.Min(VerticeX[0], VerticeX[1]), VerticeX[2]), VerticeX[3]);
dbMaxx = Math.Max(Math.Max(Math.Max(VerticeX[0], VerticeX[1]), VerticeX[2]), VerticeX[3]);
dbMiny = Math.Min(Math.Min(Math.Min(VerticeY[0], VerticeY[1]), VerticeY[2]), VerticeY[3]);
dbMaxy = Math.Max(Math.Max(Math.Max(VerticeY[0], VerticeY[1]), VerticeY[2]), VerticeY[3]);
//计算新的仿射变换参数
double[] newTransform = new double[6];
newTransform[0] = dbMinx; //左上角点x坐标
newTransform[3] = dbMaxy; //左上角点y坐标
newTransform[1] = 100; //像素宽度
newTransform[5] = -100; //像素高度
//计算大小
int width = (int)Math.Ceiling(Math.Abs(dbMaxx - dbMinx) / 100.0);
int height = (int)Math.Ceiling(Math.Abs(dbMaxy - dbMiny) / 100.0);
//创建新的栅格影像
OSGeo.GDAL.Driver pGDalDriver = Gdal.GetDriverByName("GTiff");
Dataset poDataset = pGDalDriver.Create(FilePath, width, height, 1, DataType.GDT_Float32, null);
poDataset.SetGeoTransform(newTransform);
poDataset.SetProjection(MercatorWkt);
//重投影
Gdal.ReprojectImage(ds, poDataset, ds.GetProjectionRef(), MercatorWkt, eResampleMethod, 0, 0, new Gdal.GDALProgressFuncDelegate(ProgressFunc), null, null);
//设置NoData值
Band band = poDataset.GetRasterBand(1);
band.SetNoDataValue(-10000000);
poDataset.FlushCache();
poDataset.Dispose();
}
