private List<verticalCurve> getRayIntersectionsOnTangentSegment(ptsRay aRay)
{
if (this.slopeRateOfChange_ != Double.PositiveInfinity)
throw new Exception("Parabolic profile segment encountered where tangent profile segment expected.");
if (aRay.get_m() == this.get_m())
{
if (this.get_b() == aRay.get_b())
return null;
else
throw new NotImplementedException();
}
double intersectionX = (this.get_b() - aRay.get_b()) /
(aRay.get_m() - this.get_m());
if (intersectionX < this.BeginStation.trueStation || intersectionX > this.EndStation.trueStation)
return null;
if (false == aRay.isWithinDomain(intersectionX))
return null;
int sign = 1;
verticalCurve newVC = null;
if (1 == aRay.advanceDirection)
{
newVC = new verticalCurve((CogoStation)aRay.StartPoint.x, aRay.StartPoint.z,
aRay.Slope, intersectionX - aRay.StartPoint.x, Double.PositiveInfinity);
}
else
{
sign = -1;
newVC = new verticalCurve((CogoStation)intersectionX, getElevation(this, (CogoStation)intersectionX),
sign * aRay.Slope, Math.Abs(intersectionX - aRay.StartPoint.x), Double.PositiveInfinity);
}
var returnList = new List<verticalCurve>();
returnList.Add(newVC);
return returnList;
}
private List<List<verticalCurve>> getRayIntersectionsOnParabolicSegment(ptsRay aRay)
{
List<List<verticalCurve>> returnListOfLists = null;
double xForZeroSlope = getXforSlopeZero();
var parabola0_0point = new { x = xForZeroSlope, elev = getElevation(this, (CogoStation) xForZeroSlope) };
/* in which m is slope of the ray, b is the y-intercept of the ray
* from y = mx + b
* k is the slope rate of change of the parabola
* from y = kx^2
* Solved into a quadratic equation, it is in the form of
* -kx^2 + mx + b = 0
*
* which then is solved by the quadratic formula:
* -m +/- sqrt(m^2 + 4kb)
* x = ----------------------
* -2k
*
* Finally, the part under the square root is called the discriminant.
* If the discriminant is negative, the roots are imaginary and
* we have no interest in those for our application. - Paul Schrum
* http://en.wikipedia.org/wiki/Quadratic_equation
* */
// Ray parts
double m = aRay.get_m();
double untransformedB = aRay.get_b();
double rayElevAtParabolaInflectionStation = (m * parabola0_0point.x) + untransformedB;
double b = rayElevAtParabolaInflectionStation - parabola0_0point.elev;
// parabola parts
double k = this.slopeRateOfChange_ / 2.0;
double discriminant = (m * m) + (4 * k * b);
if (discriminant < 0.0)
return null;
double sqrtDisc = Math.Sqrt(discriminant);
double xIntercept1;
double xIntercept2;
int sign = 1;
verticalCurve newVC = null;
xIntercept1 = ((-m + sqrtDisc) / (-2 * k)) + parabola0_0point.x;
if (true == aRay.isWithinDomain(xIntercept1) && true == this.isWithinDomain(xIntercept1))
{
if (1 == aRay.advanceDirection)
newVC = new verticalCurve((CogoStation)aRay.StartPoint.x, aRay.StartPoint.z,
aRay.Slope, xIntercept1 - aRay.StartPoint.x, Double.PositiveInfinity);
else
{
sign = -1;
newVC = new verticalCurve((CogoStation) xIntercept1, getElevation(this, (CogoStation)xIntercept1),
sign * aRay.Slope, Math.Abs(xIntercept1 - aRay.StartPoint.x), Double.PositiveInfinity);
}
if (null == returnListOfLists)
returnListOfLists = new List<List<verticalCurve>>();
List<verticalCurve> listOfVerticalCurves = new List<verticalCurve>();
listOfVerticalCurves.Add(newVC);
returnListOfLists.Add(listOfVerticalCurves);
}
if (discriminant > 0)
{
xIntercept2 = ((-m - sqrtDisc) / (-2 * k)) + parabola0_0point.x;
if (true == aRay.isWithinDomain(xIntercept2) && true == this.isWithinDomain(xIntercept2))
{
if (1 == aRay.advanceDirection)
{
sign = 1;
newVC = new verticalCurve((CogoStation)aRay.StartPoint.x, aRay.StartPoint.z,
aRay.Slope, xIntercept2 - aRay.StartPoint.x, Double.PositiveInfinity);
}
else
{
sign = -1;
newVC = new verticalCurve((CogoStation)xIntercept2, getElevation(this, (CogoStation)xIntercept2),
sign * aRay.Slope, Math.Abs(xIntercept2 - aRay.StartPoint.x), Double.PositiveInfinity);
}
if (null == returnListOfLists)
returnListOfLists = new List<List<verticalCurve>>();
List<verticalCurve> listOfVerticalCurves = new List<verticalCurve>();
listOfVerticalCurves.Add(newVC);
returnListOfLists.Add(listOfVerticalCurves);
}
}
return returnListOfLists;
}