Trace Interval

In order to calculate Downhole coordinates, the drillhole trace is represented by a series of straight line segments. The Trace interval defines the length of these line segments. When the drillhole bends (i.e. the surveyed azimuth and inclination values are changing), smaller Trace intervals will produce a better approximation to the actual trace.

Normally a suitable Trace interval will be in the range 5 to 20. A Trace interval less than 1 should only be used when there are abrupt changes in the drillhole trajectory. When the holes are vertical or have only a collar survey, the size of the trace interval will not affect the precision of the calculated 3D coordinates. In this case, entering a small Trace interval value will slow down the process unnecessarily.

A trace interval of 10 will produce acceptable plots for average hole deviations and commonly used plot scales. For unsurveyed holes, plotted as straight lines, large trace intervals are suitable. For small scale plots with acutely deviating holes, a very small trace interval may be required.