Be sure to pull the tape or chain the same way every time. If you are measuring a distance greater than your tape or chain you need to use chaining pins and transit to assure accuracy. When you are at the end of the chain and are on line set a chaining pin and continue as before staying on line. Please be aware that there are adjustments to the measurements to take into account temperature and humidity. These adjustments are found in any good surveying handbook, and will come with a surveyors tape.
Today there are electronic instruments that can measure using laser, infrared, and sound.
Chaining or taping is the most accurate method we have to use for period measuring. In a transit there are 3 horizontal wires and 1 vertical wire. The center horizontal wire is used for normal sights. The top and bottom wires are the stadia lines. The principal is relatively simple when you take a reading at 100 the distance between the top and bottom wires is 1 .