Definition
A blank CHART, usually on the MERCATOR PROJECTION, showing only the GRATICULE and a COMPASS ROSE, so that the plotting sheet can be used for any LONGITUDE. In hydrographic SURVEYING, a working sheet on which the main STATIONS of the SURVEY are plotted. It forms the framework of the SURVEY and provides the basis for accurately locating and plotting all the detail of the SURVEY. See also LATTICE.