Romer 227282 208400855 2008-04-26T21:46:13Z MisfitToys 58947 {{About|the mechanism|the name|Romer (surname)|the lunar crater|Römer (crater)|the building in Frankfurt|Römer}} A '''Romer''' or '''Roamer''' is a simple device for accurately plotting a [[grid reference]] on a [[map]]. Essentially, it is a specially marked out [[ruler]] which matches the scale of the map in use. The scales are laid out in reverse such that by lining up the numbers given in the grid reference with the gridlines for the square in question, the corner of the romer lies on the referenced spot. A small hole at this point allows the location to be marked with a pencil. Romers are generally made from transparent plastic so the map can be viewed through them. They are an essential piece of equipment for [[rallying]], and any other use of maps where accuracy is needed. The illustration below shows how the romer is used. Here, we are plotting the reference 696018. The marks corresponding to (6, 8) on the romer are lined up along the gridlines (69, 01). The hole in the corner yields the exact point, the church at Little Plumpton. [[Image:Fictional_Map_With_Romer.jpg]] [[Category:Cartography]] [[Category:Navigation]] [[Category:Road rallying]] [[it:Coordinatometro]]