The LUGRID grid system has been designed by the National Museum of Natural History of Luxembourg to allow for biological grid based recording of species. It is based on LUREF reference frame and is based on a division along the x and y lines of the Gauss-Luxembourg coordinate system into four 100 km square areas LA, LB, LC, LD . Grids can have 10km, 1km, 0.1 km or 0.001 km sizes. The grids are written as follows: two letter symbols (LA, LB, LC or LD) two groups of equal amount of number symbols. The amount of number symbols in each group indicates the resolution of the grid: 1 number (eg. LC 3 4) -> 10km grid, 2 numbers (eg. LC 34 45) - >1 km grid, 3 (eg. LC 342 458) - > 0.1 km grid, 3 numbers (eg. LC 3429 4581 -> 0.01 km grid