A contour line should not fork or divide. Contours cannot branch or wye into two contours of the same elevation. Controlling features in locating contours are usually drainage lines. Contour lines crossing a stream point upstream and form form V's. Contour lines crossing a ridge crest point down the ridge and form U's.
Contour lines go in pairs up valleys and sides of ridges.
Then tend to parallel streams. Contours cross sloping, crowned streets in typical U-shaped curves. The proper rod reading that will mark a contour is determined. The rodperson selects trial points and is directed uphill or downhill until the required rod reading is secured. Indirect Method Rod readings are taken at critical points and changes in the ground slope.