romer
/ˈrəʊmə(r)/noun
- a small piece of plastic or card bearing perpendicularly aligned scales or (if transparent) a grid, used to determine the precise reference of a point within the grid printed on a map坐标格网尺, 坐标展点尺。
词源
1930s: named after Carrol Romer （1883-1951）, its British inventor.