Banded Contour Charts

Extract

A chart is the data base to which other navigational information is related and yet has to serve ships of widely different draughts. A possible alternative providing more draught-specific information based largely on currently available hardware, would be the creation of ‘banded contour charts’ on microfilm. Produced directly from a computer data bank by a fast flying light-spot microfilm plotter, the master charts would be single frames of 35 mm microfilm mounted in cards 183 by 83 mm. A set of micro-charts would be produced covering the same sea area and differing only in that each has a different, limited band of depth contours of critical importance to ships in a limited draught range: for example, the first going from 0 to 5 metres by 1-metre intervals, the second from 3 to 8, the third from 5 to 10 and so on. All other data, including spot depths outside the contours, would be the same on all charts in the series.