COREMAP is a data system for recording and processing information from drill cores and boreholes. The system may also be used in tunnels, adits, etc. The standard sheets include general, geological, chemical, joint, and borehole deviation data, but these may be extended to include any other type of information. In COREMAP it is also possible to computerize notes.The processing routines of COREMAP include decoded lists, lists of any specified parameter or parameters, brief descriptions of the core by histograms, and a number of plotted maps. Different types of planar and section maps are plotted on a drum or a microfilm plotter. The projections are corrected for borehole deviation and the strike and the dip of the rocks. The length of each analyzed interval is plotted together with one chemical element. COREMAP is a sister system of GEOMAP, the field data system for hard rocks. The two systems comprise a valuable tool in prospecting and geological mapping.