private Coordinate GetFieldFromGps(Gps gps)
{
var x = (int)((gps.Longitude - XLowerLeftCorner) / CellSize);
var y = (int)((gps.Latitude - YLowerLeftCorner) / CellSize);
return(new Coordinate(x, y));
}
/// <summary>
/// Retrieves a pixel value at a position from GPS.
/// </summary>
/// <param name="gps">A Gps position for the desired pixel.</param>
/// <returns>The value of the pixel.</returns>
public double GetValueFromGps(Gps gps)
{
if (gps.Longitude < XLowerLeftCorner || gps.Longitude > XLowerLeftCorner + NumberOfColumns * CellSize ||
gps.Latitude < YLowerLeftCorner || gps.Latitude > YLowerLeftCorner + NumberOfRows * CellSize)
{
return(NoDataValue);
}
var coordinate = GetFieldFromGps(gps);
return(GetValue(coordinate));
}
public double DistanceTo(Gps targetGps)
{
var theta = Longitude - targetGps.Longitude;
var thetaRad = Math.PI * theta / 180;
var baseRad = Math.PI * Latitude / 180;
var targetRad = Math.PI * targetGps.Latitude / 180;
var dist = Math.Sin(baseRad) * Math.Sin(targetRad) +
Math.Cos(baseRad) * Math.Cos(targetRad) * Math.Cos(thetaRad);
dist = Math.Acos(dist);
dist = dist * 180 / Math.PI;
dist = dist * 60 * 1.1515;
const double kilometers = 1.609344;
return(kilometers * dist);
}
