A rod is a unit of length, equal to 11 cubits, 5.0292 meters, or 16.5 feet. A rod is the same length as a perch and a pole. The lengths of the perch (one rod) and chain (four rods) were standardized in 1607 by Edmund Gunter. The length is equal to the standardized length of the ox goad used by medieval English plowmen; fields were measured in acres which were one chain (four rods) by one furlong (in the United Kingdom, ten chains). The rod is still in use as a unit of measure in certain specialized fields. In recreational canoeing, maps measure portages (overland paths where canoes must be carried) in rods. This is thought to persist due to the rod approximating the length of a typical canoe. In the United Kingdom, the sizes of allotment gardens continue to be measured in rods.