Edmund Gunter (1581-1626) Surveying is important to the engineering of any large construction project. For example, it is impossible to imagine laying out a railroad or canal without professionally trained and careful surveyors helping with the project. When you think about a project as big as the transcontinental railroad, which had the added complexity of two railroads being built separately with the plan to meet in the middle of the country, it is an impossible task without surveyors. It is hard to determine when surveying started, however. The Egyptians certainly knew something about surveying, because the siting, angles, and dimensions of the Great Pyramid are nearly perfect. The Romans had surveyors helping to lay out their roads, aqueducts, and cities as complex as Pompeii. But something like modern surveying started with the invention of the Gunter's chain, which was introduced by mathematician Edmund Gunter in 1620. The Gunter's chain is a tool for accurately measuring distances. It has 100 links in the chain with a total length of 66 feet (20 meters). A piece of land one chain wide by ten chains long is an acre. Early surveyors needed three pieces of equipment: a Gunter's chain, a plane table with transit or circumferentor, and a surveying compass. With these tools they could orient themselves, sight lines, record angles, and accurately measure distances. This was sufficient for laying out boundary lines. To measure grades or elevations, a topographer's rod was used Today all of this is handled with a computerized, GPS-enabled device called a "total station." It includes the transit/theodolite and combines it with EDM (electronic distance measuring). A helper stands with a reflector and, once sighted, the total station measures and records angles and distances. There are also robotic total stations to eliminate the need for a helper. Compared to the tools that preceded them, total stations make surveying on civil engineering projects incredibly easy. But the principles are all the same: get your bearings, then measure angles, distances, and elevations. With these techniques, civil engineers can lay out the biggest projects people can imagine.