Survey Calculation Method survCalcMethType extSurvCalcMethType UKOOA 1.0 tangential Uses only the inclination and direction angles measured at the lower end of the course length. The borehole path is assumed to be tangent to these angles through the course. balanced tangential Uses the inclination and direction angles at the top and bottom of the course length in a manner so as to tangentially balance the two sets of measured angles over the course length. Results obtained are the same as the acceleration, trapezoidal, and vector averaging methods. average angle Uses the angles measured at both the top and bottom of the course length in such a fashion that the average of the two sets of measured angles is the assumed inclination and direction. The borehole survey is then calculated tangentially using these averaged angles over the course length. radius of curvature Uses the sets of angles measured at the top and bottom of the course length to generate a space curve (representing the borehole path) that has the shape of a spherical arc passing through the measured angles at both the upper and lower ends of the measured course. minimum curvature Uses the sets of angles measured at the top and bottom of the course length to establish coordinate velocities through which a space curve (which represents the calculated path of the borehole) passes in a manner that minimizes its total curvature. circular arc Uses both sets of measured angles associated with each course length to recreate the borehole path as a sequence of small circular arcs constrained by the measured angles to pass through the end points with inclination and direction angles as measured. Simpsons rule Uses as many measured angle values as are available (a minimum of three sets) to recreate the borehole path through Simpsons Rule for numeric integration, which approximates by passing a parabola through three points.