/// <summary>
/// Computes an IDW surface interpolation using a gradient to take into account differces from a raster
/// Usefull for climatological data as perform a temperature correction based on terrain elevation
/// </summary>
/// <param name="OutputGTiffFile"></param>
public static void IdwTemperaturesWithElevationCorrection(string OutputGTiffFile, List <Geometry> Points)
{
// Datos del malla de salida
int EPSG = 23030;
double CellSize = 10000;
double CellSizeX = CellSize;
double CellSizeY = CellSize;
double xMin = 360000;
double yMax = 4830000;
int NumCols = 59;
int NumRows = 39;
double yMin = yMax - (NumRows * CellSize);
double xMax = xMin + (NumCols * CellSize);
var CorrectionGradient = -0.65d;
var IdwExponent = 3d;
//---------------------------------------------
// Filter points with NoData in value or in elevation
//---------------------------------------------
Points = Points.Where(po => !double.IsNaN(po.GetM(0)) && !double.IsNaN(po.GetZ(0))).ToList();
logger.Trace($"INICIANDO con {Points.Count} termómetros.");
//---------------------------------------------
// Compute weights for each point and raster cell
//---------------------------------------------
var weights = new Dictionary <Geometry, double[, ]>();
var locker = new object();
Parallel.ForEach(Points, (p) => {
double dXPunto = p.GetX(0);
double dYPunto = p.GetY(0);
// Para cada celda del mallado de la aplicación
double[,] coeficients = new double[NumRows, NumCols];
for (int i = 0; i < NumRows; i++)
{
for (int j = 0; j < NumCols; j++)
{
double CellX = xMin + (j * CellSizeX) + (CellSizeX / 2);
double CellY = yMax - ((i * CellSizeY) + (CellSizeY / 2));
// Se calcula la distancia entre celda y punto como número de pasos, para evitar valores muy grandes
double distancia = System.Math.Sqrt(System.Math.Pow((dXPunto - CellX), 2) / (CellSizeX) + System.Math.Pow((dYPunto - CellY), 2) / (CellSizeY));
distancia = Math.Max(distancia, 0.0000001d);
// Se calculan coeficientes, multiplicados por una costante, para evitar valores muy pequeños
coeficients[i, j] = (1 / (System.Math.Pow(distancia, IdwExponent))) * (10 ^ 3);
}
}
lock (locker) weights.Add(p, coeficients);
});
logger.Trace($"Pesos computados.");
//---------------------------------------------
// Compute elevations for each raster cell from DEM
// AKIIII => read with gdal, retornar double.NAN en caso de nulo
//---------------------------------------------
double GetElevation(double x, double y)
{
return(200d);
};
//---------------------------------------------
// Compute raster values
//---------------------------------------------
var ResultData = new float[NumRows, NumCols];
for (int i = 0; i < NumRows; i++)
{
for (int j = 0; j < NumCols; j++)
{
ResultData[i, j] = float.NaN;
}
}
double CellValue;
double WeightsSum;// Acumula la suma de los coeficientes válidos para luego dividir por ella
//------------------------------------------------------------
// Iterar por todas las celdas del mallado a crear
//------------------------------------------------------------
for (int i = 0; i < NumRows; i++)
{
logger.Trace($"Tratando fila {i} de {NumRows}.");
for (int j = 0; j < NumCols; j++)
{
// Inicializar
CellValue = 0d;
WeightsSum = 0d;
//------------------------------------------------------------
// Calcular el valor para la celda i,j
//------------------------------------------------------------
// Obtner el sumatorio de los C1V1 + C2V2 + ... + CnVn
foreach (var p in Points)
{
double dValAux = p.GetM(0);
double Elevation = p.GetZ(0);
if (!double.IsNaN(dValAux))
{
//-------------------------------------------------------------------------
// Aplicamos corrección de valor por cota:
// Búsqueda de la cota de la celda
//-------------------------------------------------------------------------
double dCeldaX = xMin + (i * CellSizeX) + (CellSizeX / 2d);
double dCeldaY = yMax - ((j * CellSizeY) + (CellSizeY / 2d));
// Get current cell elevation
double CellElevation = GetElevation(dCeldaX, dCeldaY);
//------------------------------------------------------------------------------------------
// No se aplica el gradiente termométrico a las celdas sobre las que no tenemos cota
//------------------------------------------------------------------------------------------
if (!double.IsNaN(CellElevation))
{
//---------------------------------------------
// Cálculo del valor de temperatura modificado
//---------------------------------------------
dValAux += CorrectionGradient * (CellElevation - Elevation) / 100;
}
double weight = weights[p][i, j];
CellValue += weight * dValAux;
WeightsSum += weight;
}
}
// Obtener el valor dividiendo por SUM(C1 ... Cn)
if (WeightsSum != 0)
{
ResultData[i, j] = (float)(CellValue / WeightsSum);
}
}
}
// Create results raster
logger.Trace($"Creando gtif...");
var datos = new float[NumRows * NumCols];
var cont = 0;
for (int i = NumRows - 1; i >= 0; i--)
{
for (int j = 0; j < NumCols; j++)
{
datos[cont] = ResultData[i, j];
cont++;
}
}
// Create output GTiff
if (File.Exists(OutputGTiffFile))
{
File.Delete(OutputGTiffFile);
}
string EsriWkt = GdalUtils.EPSG2WKT(EPSG);
var GeoTrans = new[] { xMin, CellSize, 0, yMin, 0, CellSize };
GdalUtils.CreateRaster("GTiff", OutputGTiffFile, NumRows, NumCols, xMin, yMin, CellSize, EsriWkt, GeoTrans, new List <float[]>()
{
datos
}, null, null);
logger.Trace($"Creado {OutputGTiffFile}");
}
public static void Info(string FileName, bool ShowBands)
{
try
{
/* -------------------------------------------------------------------- */
/* Open dataset. */
/* -------------------------------------------------------------------- */
Dataset ds = Gdal.Open(FileName, Access.GA_ReadOnly);
if (ds == null)
{
Console.WriteLine("Can't open " + FileName);
System.Environment.Exit(-1);
}
Console.WriteLine("Raster dataset parameters:");
Console.WriteLine(" Projection: " + ds.GetProjectionRef());
Console.WriteLine(" RasterCount: " + ds.RasterCount);
Console.WriteLine(" RasterSize (" + ds.RasterXSize + "," + ds.RasterYSize + ")");
/* -------------------------------------------------------------------- */
/* Get driver */
/* -------------------------------------------------------------------- */
Driver drv = ds.GetDriver();
if (drv == null)
{
Console.WriteLine("Can't get driver.");
System.Environment.Exit(-1);
}
Console.WriteLine("Using driver " + drv.LongName);
/* -------------------------------------------------------------------- */
/* Get metadata */
/* -------------------------------------------------------------------- */
string[] metadata = ds.GetMetadata("");
if (metadata.Length > 0)
{
Console.WriteLine(" Metadata:");
for (int iMeta = 0; iMeta < metadata.Length; iMeta++)
{
Console.WriteLine(" " + iMeta + ": " + metadata[iMeta]);
}
Console.WriteLine("");
}
/* -------------------------------------------------------------------- */
/* Report "IMAGE_STRUCTURE" metadata. */
/* -------------------------------------------------------------------- */
metadata = ds.GetMetadata("IMAGE_STRUCTURE");
if (metadata.Length > 0)
{
Console.WriteLine(" Image Structure Metadata:");
for (int iMeta = 0; iMeta < metadata.Length; iMeta++)
{
Console.WriteLine(" " + iMeta + ": " + metadata[iMeta]);
}
Console.WriteLine("");
}
/* -------------------------------------------------------------------- */
/* Report subdatasets. */
/* -------------------------------------------------------------------- */
metadata = ds.GetMetadata("SUBDATASETS");
if (metadata.Length > 0)
{
Console.WriteLine(" Subdatasets:");
for (int iMeta = 0; iMeta < metadata.Length; iMeta++)
{
Console.WriteLine(" " + iMeta + ": " + metadata[iMeta]);
}
Console.WriteLine("");
}
/* -------------------------------------------------------------------- */
/* Report geolocation. */
/* -------------------------------------------------------------------- */
metadata = ds.GetMetadata("GEOLOCATION");
if (metadata.Length > 0)
{
Console.WriteLine(" Geolocation:");
for (int iMeta = 0; iMeta < metadata.Length; iMeta++)
{
Console.WriteLine(" " + iMeta + ": " + metadata[iMeta]);
}
Console.WriteLine("");
}
string GetPosition(Dataset ds, double column, double row)
{
var d = GdalUtils.GDALInfoGetPosition(ds, column, row);
return($"{d[0].ToString()} , {d[1].ToString()} ");
}
/* -------------------------------------------------------------------- */
/* Report corners. */
/* -------------------------------------------------------------------- */
Console.WriteLine("Corner Coordinates:");
Console.WriteLine(" Upper Left (" + GetPosition(ds, 0.0, 0.0) + ")");
Console.WriteLine(" Lower Left (" + GetPosition(ds, 0.0, ds.RasterYSize) + ")");
Console.WriteLine(" Upper Right (" + GetPosition(ds, ds.RasterXSize, 0.0) + ")");
Console.WriteLine(" Lower Right (" + GetPosition(ds, ds.RasterXSize, ds.RasterYSize) + ")");
Console.WriteLine(" Center (" + GetPosition(ds, ds.RasterXSize / 2, ds.RasterYSize / 2) + ")");
Console.WriteLine("");
/* -------------------------------------------------------------------- */
/* Report projection. */
/* -------------------------------------------------------------------- */
string projection = ds.GetProjectionRef();
if (projection != null)
{
SpatialReference srs = new SpatialReference(null);
if (srs.ImportFromWkt(ref projection) == 0)
{
string wkt;
srs.ExportToPrettyWkt(out wkt, 0);
Console.WriteLine("Coordinate System is:");
Console.WriteLine(wkt);
}
else
{
Console.WriteLine("Coordinate System is:");
Console.WriteLine(projection);
}
}
/* -------------------------------------------------------------------- */
/* Report GCPs. */
/* -------------------------------------------------------------------- */
if (ds.GetGCPCount( ) > 0)
{
Console.WriteLine("GCP Projection: ", ds.GetGCPProjection());
GCP[] GCPs = ds.GetGCPs();
for (int i = 0; i < ds.GetGCPCount(); i++)
{
Console.WriteLine("GCP[" + i + "]: Id=" + GCPs[i].Id + ", Info=" + GCPs[i].Info);
Console.WriteLine(" (" + GCPs[i].GCPPixel + "," + GCPs[i].GCPLine + ") -> ("
+ GCPs[i].GCPX + "," + GCPs[i].GCPY + "," + GCPs[i].GCPZ + ")");
Console.WriteLine("");
}
Console.WriteLine("");
double[] transform = new double[6];
Gdal.GCPsToGeoTransform(GCPs, transform, 0);
Console.WriteLine("GCP Equivalent geotransformation parameters: ", ds.GetGCPProjection());
for (int i = 0; i < 6; i++)
{
Console.WriteLine("t[" + i + "] = " + transform[i].ToString());
}
Console.WriteLine("");
}
/* -------------------------------------------------------------------- */
/* Get raster band */
/* -------------------------------------------------------------------- */
for (int iBand = 1; iBand <= ds.RasterCount && ShowBands; iBand++)
{
Band band = ds.GetRasterBand(iBand);
Console.WriteLine("Band " + iBand + " :");
Console.WriteLine(" DataType: " + Gdal.GetDataTypeName(band.DataType));
Console.WriteLine(" ColorInterpretation: " + Gdal.GetColorInterpretationName(band.GetRasterColorInterpretation()));
ColorTable ct = band.GetRasterColorTable();
if (ct != null)
{
Console.WriteLine(" Band has a color table with " + ct.GetCount() + " entries.");
}
Console.WriteLine(" Description: " + band.GetDescription());
Console.WriteLine(" Size (" + band.XSize + "," + band.YSize + ")");
int BlockXSize, BlockYSize;
band.GetBlockSize(out BlockXSize, out BlockYSize);
Console.WriteLine(" BlockSize (" + BlockXSize + "," + BlockYSize + ")");
double val;
int hasval;
band.GetMinimum(out val, out hasval);
if (hasval != 0)
{
Console.WriteLine(" Minimum: " + val.ToString());
}
band.GetMaximum(out val, out hasval);
if (hasval != 0)
{
Console.WriteLine(" Maximum: " + val.ToString());
}
band.GetNoDataValue(out val, out hasval);
if (hasval != 0)
{
Console.WriteLine(" NoDataValue: " + val.ToString());
}
band.GetOffset(out val, out hasval);
if (hasval != 0)
{
Console.WriteLine(" Offset: " + val.ToString());
}
band.GetScale(out val, out hasval);
if (hasval != 0)
{
Console.WriteLine(" Scale: " + val.ToString());
}
for (int iOver = 0; iOver < band.GetOverviewCount(); iOver++)
{
Band over = band.GetOverview(iOver);
Console.WriteLine(" OverView " + iOver + " :");
Console.WriteLine(" DataType: " + over.DataType);
Console.WriteLine(" Size (" + over.XSize + "," + over.YSize + ")");
Console.WriteLine(" PaletteInterp: " + over.GetRasterColorInterpretation().ToString());
}
}
}
catch (Exception e)
{
Console.WriteLine("Application error: " + e.Message);
}
}