Plotter for Use with Polar Plots From an Alidade Plotter

摘要

A plotter is disclosed for plotting maps from plots obtained from surveys carried out using a polar alidade. The plotter has a rotary cursor 10 which can be fixed over a plot in an area 13. The cursor comprises an arm 12 adjustable in length and coupled to a pivot arm 14 at a variable distance from the centre of a rotary carriage 11 which is positioned at the plot centre. The cursor is so linked (i.e. via carriages 15, 21 on bars 17, 23) to a pointer arm 18 that by moving the pointer arm end 19 over a plotting table 28 the cursor 10 can be positioned in a predetermined angular alignment with a line from a mark on the plot to the plot centre, and the distance between the centre of the carriage 11 and the pivot arm 14 can be set proportional to the distance associated with that point. A point on a required map can then be plotted from the position of the pointer arm end 19. In another plotting method a further similar cursor may be used, with another plot of the same area. The arm 12 carries a scale and the area 13 an angular scale, both scales being viewed by an optical system. A second cursor 30 and arm 32 similar to cursor 10 and arm 12 are also present. IMAGE