public static Extent TransformExtent(this CoordinateTransformation coordinateTransformation, Extent extent)
{
Extent destExtent = null;
if (coordinateTransformation != null && extent != null)
{
double[] xs = { extent.MinX, extent.MaxX };
double[] ys = { extent.MinY, extent.MaxY };
double[] zs = { 0, 0 };
coordinateTransformation.TransformPoints(2, xs, ys, zs);
double minX, minY, maxX, maxY;
if (xs[0] > xs[1])
{
minX = xs[1];
maxX = xs[0];
}
else
{
minX = xs[0];
maxX = xs[1];
}
if (ys[0] > ys[1])
{
minY = ys[1];
maxY = ys[0];
}
else
{
minY = ys[0];
maxY = ys[1];
}
destExtent = new Extent(minX, minY, maxX, maxY);
}
return(destExtent);
}
public static void Transform(Proj4Projection src, Proj4Projection dst,
double[] x, double[] y, double[] z)
{
lock (lockObj)
{
//Proj4Projection.CheckInitialized(src);
//Proj4Projection.CheckInitialized(dst);
if (x == null)
{
throw new ArgumentException("Argument is required", "x");
}
if (y == null)
{
throw new ArgumentException("Argument is required", "y");
}
if (x.Length != y.Length || (z != null && z.Length != x.Length))
{
throw new ArgumentException("Coordinate arrays must have the same length");
}
CoordinateTransformation trans = new CoordinateTransformation(src.srs, dst.srs);
trans.TransformPoints(x.Length, x, y, z);
}
}
// 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();
}
public static List <ICoordinate> TransformPoints(this CoordinateTransformation coordinateTransformation, IEnumerable <Coordinate> coords)
{
List <ICoordinate> destCoords = new List <ICoordinate>();
if (coordinateTransformation != null && coords != null)
{
var firstCoord = coords.FirstOrDefault();
if (firstCoord != null)
{
var count = coords.Count();
var dimension = firstCoord.Dimension;
if (dimension >= 2)
{
double[] xs = new double[count];
double[] ys = new double[count];
double[] zs = new double[count];
int i = 0;
foreach (var coord in coords)
{
xs[i] = coord[0];
ys[i] = coord[1];
if (dimension > 2)
{
zs[i] = coord[2];
}
i++;
}
coordinateTransformation.TransformPoints(count, xs, ys, zs);
for (int j = 0; j < xs.Length; j++)
{
var coord = new Coordinate(xs[j], ys[j]);
if (dimension > 2)
{
coord.Z = zs[j];
}
destCoords.Add(coord);
}
}
}
}
return(destCoords);
}
private static void TransformWKT(object srcProj, object dstProj, EPSGType srcType, EPSGType dstType, ref string wkt)
{
try
{
GdalConfiguration.ConfigureOgr();
SpatialReference src = new SpatialReference("");
switch (srcType)
{
case EPSGType.OGC_WKT:
string srcProj_str = srcProj.ToString();
src.ImportFromWkt(ref srcProj_str);
break;
case EPSGType.PROJ4:
src.ImportFromProj4(srcProj.ToString());
break;
case EPSGType.EPSG_NUM:
src.ImportFromEPSG((int)srcProj);
break;
}
SpatialReference dst = new SpatialReference("");
switch (dstType)
{
case EPSGType.OGC_WKT:
string dstProj_str = dstProj.ToString();
dst.ImportFromWkt(ref dstProj_str);
break;
case EPSGType.PROJ4:
dst.ImportFromProj4(dstProj.ToString());
break;
case EPSGType.EPSG_NUM:
dst.ImportFromEPSG((int)dstProj);
break;
}
CoordinateTransformation coordinate = Osr.CreateCoordinateTransformation(src, dst);
string wktType = wkt.Split('(')[0];
wkt = wkt.Split('(')[2].Split(')')[0];
string[] splitWKT = wkt.Split(',');
double[] xPoints = new double[splitWKT.Length];
double[] yPoints = new double[splitWKT.Length];
for (int i = 0; i < splitWKT.Length; i++)
{
double.TryParse(splitWKT[i].Split(' ')[0], out xPoints[i]);
double.TryParse(splitWKT[i].Split(' ')[1], out yPoints[i]);
}
coordinate.TransformPoints(splitWKT.Length, xPoints, yPoints, null);
wkt = wktType + "((";
for (int i = 0; i < xPoints.Length; i++)
{
wkt += xPoints[i] + " " + yPoints[i] + ",";
}
wkt = wkt.Substring(0, wkt.Length - 1);
wkt += "))";
}
catch (Exception e)
{
Debug.WriteLine(e.ToString());
}
}
