On a surveying crew, the rodman holds the rod, which is typically a red and white striped pole with a point at one end. The rod is held over a point (such as a traverse point) to allow the instrument man to sight the point with a transit or theodolite.

The rod must be held plumb (ie, perfectly vertical), and the instrument man may use hand signals to tell the rodman to lean the rod one way or the other if it doesn't show up as plumb next to the cross hairs.

If the distance is short, a plumb bob or chain and chaining may be used instead of the rod. Sometimes, no rod is needed, since the instrument can see the point directly.

At long distances (more than 1,000 feet), sighting the rod can be very difficult, since heat from the ground can cause the air to waver. The instrument man must tinker - sometimes for a couple of minutes - with the instrument to line it up exactly. This requires great patience on the rodman's part, since the rod must be perfectly still and plumb the whole time.

See: land surveying.

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