The Swedish grid (in

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

Rikets Nät, RT 90) is a

coordinate system In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine and standardize the position of the points or other geometric elements on a manifold such as Euclidean space. The coordinates are ...

that was previously used for government maps in

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

. RT 90 is a slightly modified version of the RT 38 from 1938. RT 90 has been replaced with SWEREF 99 as the official Swedish spatial reference system. While the system could be used with

negative numbers In mathematics, a negative number is the opposite of a positive real number. Equivalently, a negative number is a real number that is less than zero. Negative numbers are often used to represent the magnitude of a loss or deficiency. A debt th ...

to represent all four "quarters" of the earth (NE, NW, SE, and SW hemispheres), the standard application of RT 90 is only useful for the northern half of the eastern hemisphere where numbers are positive. The coordinate system is based on metric measures rooting from the crossing of the

Prime Meridian A prime meridian is an arbitrarily chosen meridian (geography), meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. On a spheroid, a prime meridian and its anti-meridian (the 180th meridian ...

and the

Equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

at 0,0. The Central Meridian used to be based on a meridian located at the old observatory in Stockholm, but today it is based on the Prime Meridian at Greenwich. The numbering system's first digit represents the largest distance, followed by what can be seen as fractional decimal digits (though without an explicit decimal point). Therefore, X 65 is located halfway between X 6 and X 7. The coordinate grid is specified using two numbers, named X and Y, X being the south–north axis and Y the west–east axis. Two seven-digit numbers are sufficient to specify a location with a one m resolution. Example: X=6620000 Y=1317000 (X is the northing and Y is the easting) denotes a position 6620 km north of the Equator and -183 km (1317 km-1500 km) west of the Central Meridian, which happens to be somewhere near the town center of

Arvika Arvika is a locality and the seat of Arvika Municipality, Värmland County, Sweden with 14,244 inhabitants in 2010. Geography The town of Arvika is situated at Kyrkviken, a bay of Glafsfjorden, Sweden's only inland fjord, a remnant of the tim ...

RT90 Map Projection Parameters

References

Three-dimensional systems: SWEREF 99
Lantmäteriet (Swedish Land Survey).
Two-dimensional systems: RT 90
Lantmäteriet (Swedish Land Survey). Geography of Sweden Geographic coordinate systems {{Sweden-geo-stub