Swedish grid

Swedish Grid (in Swedish Rikets Nät, RT90) is the coordinate system used for government maps in Sweden.

While negative numbers could be used to represent all four "quarters" of the earth (NE, NW, SE, and SW hemispheres) standard application of RT90 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 and the Equator at 0,0. The numbering systems first number represents the largest distance, followed by what can be seen as decimals. As such, X 65 is located half way between X 6 and X 7.

The coordinate grid is specified using two numbers, confusingly named X and Y but having inverted positions from mathematical graphs. X being the north - south axis and y the east - west axis.