FIGURE 21.-Charleston, S.C., 1:62,500-scale storm evacuation map. This type of map is prepared by NOS from USGS base maps. They are designed to aid evacuation due to flooding and show only enough planimetric detail for that purpose. This general area is also shown in appendix figures 17, 18, 19, 30, and 34.

FIGURE 22.—Marblehead Harbor, Mass., 1:10,000-scale shoreline map. These NOS maps show precisely determined high and low waterlines and limited planimetry and are used in chart construction. Scales range from 1:5,000 to 1:20,000. Part of this area is shown in appendix figure 23.

FIGURE 23.—Beverly Cove, Mass., 1:5,000-scale shoreline map. These NOS maps are stored on film, and diazo copies are reproduced on request. Shoreline maps dating from the early 19th century are available. This area is included in appendix figure 22.

FIGURE 24.-Block Island Sound and Eastern Long Island Sound, N.Y.-Conn.-N.J., 1:210,000-scale tidal current chart. This NOS chart shows current direction and spring speed in knots. Data are based on predicted times and velocities at a selected location. The charts are available for major harbors.

FIGURE 25.-Charleston Harbor, S.C., tidal current predictions from NOS.