1. A method of locating an elongated object in a three dimensional data array, comprising: selecting a slice of data generally lengthways of the elongated object; identifying points on the object in the selected slice; transposing data including the points parallel to the slice and transversely to the elongated object to align the points in a direction parallel to the slice and transverse to the elongated object; selecting a current slice rotated around the length direction of the object relative to the previously selected slice; and repeating the identifying and transposing to align points on the object in a direction parallel to the current slice and transverse to the elongated object.