Square kilometre
Square kilometre (International spelling as used by the International Bureau of Weights and Measures) or square kilometer (American spelling), symbol km2, is a multiple of the square metre, the SI unit of area or surface area.
1 km2 is equal to:
It is also approximately equal to:
Conversely:
The symbol "km2" means (km)2, square kilometre or kilometre squared and not k(m2), kilo–square metre. For example, 3 km2 is equal to 3×(1,000m)2 = 3,000,000 m2, not 3,000 m2.
Topographical map grids are worked out in metres, with the grid lines being 1,000 metres apart.
In each case, the grid lines enclose one square kilometre.
The area enclosed by the walls of many European medieval cities were about one square kilometre. These walls are often either still standing or the route they followed is still clearly visible, such as in Brussels, where the wall has been replaced by a ring road, or in Frankfurt, where the wall has been replaced by gardens. The approximate area of the old walled cities can often be worked out by fitting the course of the wall to a rectangle or an oval (ellipse). Examples include
Parks come in all sizes; a few are almost exactly one square kilometre in area. Here are some examples:
Using the figures published by golf course architects Crafter and Mogford, a course should have a fairway width of 120 metres and 40 metres clear beyond the hole. Assuming a 6,000 metres (6,600 yd) 18-hole course, an area of 80 hectares (0.8 square kilometre) needs to be allocated for the course itself. Examples of golf courses that are about one square kilometre include:
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