/// <summary>
/// Draws a ternary plot from the passed data.
/// Assumes that the passed matrix values are all normalised in [0,1].
/// </summary>
/// <param name="matrixDictionary">dicitonary of matrices - each matrix is one index.</param>
/// <param name="keys">The names of the three indices/attributes. Also used as keys to dicitonary of matrices.</param>
public static Image DrawTernaryPlot(Dictionary <string, double[, ]> matrixDictionary, string[] keys)
{
int rowCount = matrixDictionary[keys[0]].GetLength(0);
int colCount = matrixDictionary[keys[0]].GetLength(1);
int scale = 500;
double factor = Math.Sqrt(3.0) / 2.0;
int height = (int)Math.Ceiling(500 * factor);
var histo1 = new double[scale + 1, scale + 1];
var histo2 = new double[scale + 1, scale + 1];
var histo3 = new double[scale + 1, scale + 1];
double[] triplet = new double[3];
string label1 = "Ternary Plot: ";
string label2 = string.Empty;
for (int r = 0; r < rowCount; r++)
{
for (int c = 0; c < colCount; c++)
{
triplet[0] = matrixDictionary[keys[0]][r, c];
triplet[1] = matrixDictionary[keys[1]][r, c];
triplet[2] = matrixDictionary[keys[2]][r, c];
double tripletSum = triplet.Sum();
// ignore points with low values
if (tripletSum < 0.5)
{
continue;
}
triplet = DataTools.Normalise2Probabilites(triplet);
// for testing purposes
//triplet[0] = 0.0;
//triplet[1] = 0.0;
//triplet[2] = 0.95;
// in converting to ternary plot, a+b+c = 1.0 because triplet has already been normalised
double x = triplet[0] * factor;
double y = (triplet[0] + (2 * triplet[1])) / 2;
int xCoord = scale - (int)Math.Round(x * scale);
int yCoord = scale - (int)Math.Round(y * scale);
//int yCoord = (int)Math.Round(y * scale);
// time of day
if (r < 360 || r > 1053)
{
histo3[xCoord, yCoord]++; // night blue
}
else
if (r > 360 && r < 480)
{
histo1[xCoord, yCoord]++; // morning chorus red
}
else
{
histo2[xCoord, yCoord]++;
}
label2 = "Time of Day >> RGB=(dawnChorus, day, night)";
// frequency band
//if (c > 128) histo3[xCoord, yCoord]++; // high frequency
//else
//if (c > 32) histo2[xCoord, yCoord]++; // mid frequency
//else histo1[xCoord, yCoord]++; // low frequency
//label2 = "Freq Band >> RGB=(low, mid, hi)";
// sum of index values
//if (tripletSum > 1.2) histo1[xCoord, yCoord]++;
//else
//if (tripletSum > 0.6) histo2[xCoord, yCoord]++;
//else histo3[xCoord, yCoord]++;
//label2 = "Index Sum >> RGB=(hi, mid, low)";
}
}
//histo = MatrixTools.Matrix2LogValues(histo);
//histo = MatrixTools.SquareRootOfValues(histo);
histo1 = MatrixTools.LogTransform(histo1);
histo2 = MatrixTools.LogTransform(histo2);
histo3 = MatrixTools.LogTransform(histo3);
double[,] norm1 = DataTools.normalise(histo1);
double[,] norm2 = DataTools.normalise(histo2);
double[,] norm3 = DataTools.normalise(histo3);
var stringFont = Drawing.Arial12;
//Image bmp = ImageTools.DrawMatrixWithoutNormalisationGreenScale(norm);
var bmp = ImageTools.DrawRGBMatrix(norm1, norm2, norm3); // RGB
bmp.Mutate(g =>
{
int halfWidth = scale / 2;
// draw plot outline
g.DrawLine(new Pen(Color.White, 1), 0, scale, halfWidth, scale - height);
g.DrawLine(new Pen(Color.White, 1), scale, scale, halfWidth, scale - height);
//label vertices
g.DrawText(keys[0], stringFont, Color.Wheat, new PointF(halfWidth - 15, scale - height - 15));
g.DrawText(keys[1], stringFont, Color.Wheat, new PointF(0, scale - 20));
g.DrawText(keys[2], stringFont, Color.Wheat, new PointF(scale - 40, scale - 20));
// draw label
string label = label1 + label2;
g.DrawText(label, stringFont, Color.Wheat, new PointF(30, scale - height - 40));
});
return(bmp);
}
