Cartographic Instruments

instruments used for the compilation and preparation of maps for publication. Coordinate plotters, beam compasses with base-line rulers, curves, Drobyshev rules (for drawing arcs of circumference using holes with tapered edges), and normal (Geneva) rules (for measuring lines with a precision of as much as 0.2 mm by means of two moving magnifying glasses) are used to construct the mathematical base (the cartographic grid and reference points). To transfer the cartographic image from the source to the map being drawn instruments are used that make possible reduction or magnification of the image without changing the cartographic projection of the source (pantographs, reproduction devices, and projectors), as well as transformation of the cartographic projection of the original material (cartographic converters). Drawing and engraving instruments are used in making manuscript and smooth-delineation originals of maps.