This method calculates the distance to a point only in case, when the distance is smaller then MaxDist else Utils.big will be returned. You can imagine a strip with width MaxDist along the line. If now a point lays into the strip, then this is a good one and the distance will be calculated and returned. If CheckP is true then additional to the strip a halfcircle with center P and radius Maxdist is considered and analogusly for CheckQ.
This method calculates the distance to a point only in case, when the distance is smaller then MaxDist else Utils.big will be returned. You can imagine a strip with width MaxDist along the line. If now a point lays into the strip, then this is a good one and the distance will be calculated and returned. If CheckP is true then additional to the strip a halfcircle with center P and radius Maxdist is considered and analogusly for CheckQ.
public double Distance(xy,double,bool,bool,out double);
This method calculates the distance to a point Pt. The parameter Lam can be taken to calculate the nearest point of the LineType, which is also return by the outvalue Nearest
public double Distance(xy,out double,out xy);